Information
-
Patent Grant
-
6535168
-
Patent Number
6,535,168
-
Date Filed
Friday, October 12, 200123 years ago
-
Date Issued
Tuesday, March 18, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Wong; Don
- Chen; Shih-Chao
Agents
-
CPC
-
US Classifications
Field of Search
US
- 343 700 MS
- 343 767
- 343 768
- 343 770
- 343 771
- 343 772
- 343 774
- 343 776
- 343 777
- 343 778
- 343 853
-
International Classifications
-
Abstract
A relatively small and inexpensive phased array antenna provided even if the number of radiators is increased to enhance the gain. The phased array antenna has a multilayer structure including layers where a large number of radiators (15), phase-shifting units (17) each for shifting the phase of a high-frequency signal transmitted/received by the corresponding radiator, and a distributing/synthesizing unit (14) are provided respectively. The phase-shifting circuits (17A to 17D) constituting the phase-shifting units (17) are driven by the respective driver units (12). A switch (17S) used for the phase-shifting unit is provided together with the other wiring pattern on the layer where the phase-shifting units (17) are provided.
Description
TECHNICAL FIELD
The present invention relates to a phased array antenna used for transmitting/receiving an RF signal such as a microwave to electrically adjust a beam radiation direction by controlling a phase supplied to each radiating element, and a method of manufacturing the antenna.
BACKGROUND ART
As a satellite tracking on-vehicle antenna or satellite borne antenna, a phased array antenna having many radiating elements arranged in an array has conventionally been proposed (see Technical Report AP90-75 of the Institute of Electronics, Information and Communication Engineers, and Japanese Patent Laid-Open No. 1-290301).
A phased array antenna of this type has a function of arbitrarily changing the beam direction by electronically changing the phase of a signal supplied to each radiating element.
As a means for changing the feed phase of each radiating element, a phase shifter is used.
As the phase shifter, a digital phase shifter (to be simply referred to as a phase shifter hereinafter) made up of a plurality of phase shift circuits having different fixed phase shift amounts is generally used.
The phase shift circuits are respectively ON/OFF-controlled by 1-bit digital control signals to combine the phase shift amounts of the phase shift circuits, thereby obtaining a feed phase of 0° to 360° by the whole phase shifter.
A conventional phased array antenna uses many components including semiconductor elements such as PIN diodes and GaAs FETs serving as phase shift circuits, and driver circuit components for driving the semiconductor elements.
The phase shifter applies a DC current or DC voltage to these switching elements to turn them on/off, and changes the transmission path length, susceptance, and reflection coefficient to generate a predetermined phase shift amount.
Recently in the field of low earth orbit satellite communications, communications at high data rates are required along with the wide use of the Internet and the spread of multimedia communications, and the gain of the antenna must be increased.
To implement communications at high data rates, the transmission bandwidth must be increased. Because of a shortage of the frequency resource in a low-frequency band, an antenna applicable to an RF band equal to or higher than the Ka band (about 20 GHz or higher) must be implemented.
More specifically, an antenna for a low earth orbit satellite tracking terminal (terrestrial station) must satisfy technical performance:
Frequency: 30 GHz
Antenna gain: 36 dBi
Beam scanning range: beam tilt angle of 50° from front direction
To realize this by a phased array antenna, first,
the aperture area: about 0.13 m
2
(360 mm×360 mm) is needed.
In addition, to suppress the side lobe, radiating elements must be arranged at an interval of about ½ wavelength (around 5 mm for 30 GHz) to avoid generation of the grating lobe.
To set a small beam scanning step and minimize the side lobe degradation caused by the quantization error of the digital phase shifter, the phase shift circuit used for the phase shifter is desirably made up of at least 4 bits (22.5° for the minimum-bit phase shifter).
The total number of radiating elements and the number of phase shift circuit bits used for a phased array antenna which satisfies the above conditions are given by
Number of elements for the phase shift circuit: 72×72=about 5,000
Number of phase shift circuit bits: 72×72×4=about 20,000 bits
When a high-gain phased array antenna applicable to an RF band is to be implemented by, e.g., a phased array antenna disclosed in Japanese Patent Laid-Open No. 1-290301 shown in
FIG. 18
, the following problems occur.
That is, in such a conventional phased array antenna, switching elements serving as discrete components are individually mounted on a substrate formed with wiring patterns, thereby forming a phase shifter, as shown in FIG.
18
.
However, a gain is determined depending on the area of a phased array antenna, and its arrangement interval is determined depending on the frequency band in which the antennas are to be used, as described above. Accordingly, if a high-gain phased array antenna used in a higher RF band is formed, the number of phase shifters greatly increases in accordance with a large increase in number of radiating elements, thereby greatly increasing the number of mounted components.
This increases a time required for mounting these components on the substrate and the manufacturing lead time, thereby increasing manufacturing cost.
The present invention has been made to solve the above problems, and has as its object to provide a high-gain phased array antenna applicable to an RF band.
DISCLOSURE OF INVENTION
To achieve the above object, in a phased array antenna according to the present invention, radiating elements and phase shifters are individually formed on a radiating element layer and phase control layer, respectively, and both layers are coupled by a first coupling layer to form a multilayered structure as a whole. A distribution/synthesis unit is formed on a distribution/synthesis layer, and the phase control layer and distribution/synthesis layer are coupled by a second coupling layer to form the multilayered structure as a whole. Therefore, the radiating elements and distribution/synthesis unit are eliminated from the phase control layer, thereby reducing an area in the phase control layer which is to be occupied by the radiating element and distribution/synthesis unit.
The phase control layer further has a multilayered structure in which a plurality of control signal lines for controlling the phase shifters are formed on different layers in the phase control layer. This reduces an area, which is to be occupied by the control signal lines, on the layer on which the phase shifters are formed.
The phase control layer uses a micromachine switch as an RF switch included in the phase shifter, and a number of micromachine switches are simultaneously formed by a semiconductor device manufacturing process. This can make the entire phase shifter small.
For this reason, the area of the phase control layer which defines the area of the radiating element layer can be reduced, many radiating elements are arranged, in units of several thousands, at an interval (around 5 mm) which is optimal for an RF signal of, e.g., about 30 GHz. This can implement a high-gain phased array antenna applicable to an RF band.
In addition, the switches used in each phase shifter are simultaneously formed on a phase control layer (a single substrate). Therefore, as compared to a case wherein the circuit components are individually mounted as in the prior art, the numbers of mounting components, the numbers of connections, and the numbers of assembling processes can decrease, thereby reducing the manufacturing cost of the whole phased array antenna.
Further, since a driver unit simultaneously switches the control signals output to the phase shift circuits, the phase amounts of the radiating elements set in the phase shifters are simultaneously changed, thereby instantaneously changing a radiation beam direction.
Furthermore, since the driver unit for controlling the phase shifter is comprised of a flip chip which can be formed in a small area, no space in which the driver unit is to be arranged is required, thereby forming a relatively small phased array antenna.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1
is a block diagram of a phased array antenna according to an embodiment of the present invention;
FIG. 2
is a block diagram of a driver unit;
FIG. 3
is a block diagram of a phase shifter and a phase controller;
FIG. 4
is a view for explaining a multilayered substrate structure;
FIG. 5
is a view showing a multilayered substrate structure according to another embodiment of the present invention;
FIG. 6
is a view showing a multilayered substrate structure according to still another embodiment of the present invention;
FIG. 7
is an explanatory view schematically showing the arrangement on a phase control layer;
FIG. 8
is a perspective view showing a structure of a switch;
FIG. 9
is the first view showing a process for simultaneously forming micromachine switches on the phase control layer;
FIG. 10
is the second view showing the process for simultaneously forming the micromachine switches on the phase control layer;
FIG. 11
shows views for explaining an example of mounting a switch;
FIG. 12
shows views for explaining another example of mounting the switch;
FIG. 13
shows views of the circuit arrangement in Example 1;
FIG. 14
shows views of the circuit arrangement in Example 2;
FIG. 15
shows views of the circuit arrangement in Example 3;
FIG. 16
shows views of the circuit arrangement in Example 4;
FIG. 17
shows views of the circuit arrangement in Example 5; and
FIG. 18
is a view for explaining a conventional phased array antenna.
BEST MODE OF CARRYING OUT THE INVENTION
The present invention will be described below with reference to the accompanying drawings.
FIG. 1
is a block diagram of a phased array antenna
1
according to an embodiment of the present invention.
In the following description, a phased array antenna is used as an RF signal transmission antenna. However, the phased array antenna is not limited to this, and can be used as an RF signal reception antenna for the same operation principle based on the reciprocity theorem.
In addition, when a whole antenna is made up of a plurality of subarrays, the present invention may be applied to a phased array antenna of each subarray.
FIG. 1
is a view for explaining the arrangement of the phased array antenna
1
. Referring to
FIG. 1
, the phased array antenna
1
is made up of a multilayered substrate unit
2
on which antenna radiating elements, phase control circuits, and the like are mounted on a multilayered substrate, a feeder
13
for feeding RF power to the multilayered substrate unit
2
, a control unit
11
for controlling the phase of each radiating element of the multilayered substrate unit
2
, and a driver unit
12
for individually driving phase shifters.
In
FIG. 1
, m×n (m and n are integers of 2 or more) radiating elements
15
are arranged in an array, and RF signals are supplied to the radiating elements
15
from the feeder
13
via a distribution/synthesis unit
14
, strip lines
16
, and phase shifters
17
.
Note that, the radiating elements
15
may be arranged in a rectangular matrix shape or any other shape such as a triangular shape.
Many control signal lines
53
(in the aforementioned example, the total number of phase shifters
17
is about 5,000 units) for connecting the phase shifters
17
to the phase shift units
16
and the active regions
12
to the phase shifters
17
are simultaneously formed on the phased array antenna
1
by photolithography and etching.
The control unit
11
calculates the feed phase shift amount of each radiating element
15
on the basis of a desired beam radiation direction.
The calculated phase shift amounts of respective calculated radiating elements
15
are distributed from the control unit
11
to the p driver units
12
by control signals
11
i
to
11
p
(one of these control signals may be called as a control signal
11
i
). In one driver unit
12
, the phase shift amounts of the q radiating elements
17
are serially input. In this case, p×q is basically equal to the total number of m×n radiation elements, but becomes slightly larger than the number of total radiation elements depending on the number of output terminals of the driver units
12
.
FIG. 2
is a block diagram of the driver unit
12
.
The driver unit
12
is comprised of a data distributor
41
and q phase controllers
42
arranged for the respective phase shifters
17
.
The driver unit
12
serially receives the phase shift amounts of the q radiating elements
15
.
The data distributor
41
distributes the phase shift amounts of the q radiating element
15
included in a control signal
11
i
to the q phase controllers
42
respectively connected to the phase shifters
17
.
Then, the phase shift amounts of the radiating elements
15
are set in corresponding phase controllers
42
.
As shown in
FIG. 1
, the control unit
11
outputs a trigger signal Trg to each driver unit
12
.
The trigger signal Trg is input to each phase controller
42
of the driver unit
12
, as shown in FIG.
2
.
The trigger signal Trg determines a timing in which each phase shift amount set in the phase controller
42
is designated and output to a corresponding phase shifter
17
.
Therefore, after the phase shift amounts are respectively set in the phase controllers
42
, the controller
11
outputs the pulse-like trigger signal Trg to simultaneously update the feed phase shift amounts to the respective radiating elements
15
, thereby instantaneously changing the beam radiation direction.
The phase shifter
17
arranged for each radiating element
15
and the phase controller
42
of the driver unit
12
will be described with reference to FIG.
3
.
FIG. 3
is a block diagram showing the phase shifter
17
and the phase controller
42
.
In this case, the phase shifter
17
is made up of four phase shift circuits
17
A to
17
D having different phase shift amounts of 22.5°, 45°, 90°, and 180°.
The phase shift circuits
17
A to
17
D are connected to a strip line
16
for propagating an RF signal from the distribution/synthesis unit
14
to the radiating element
15
.
In particular, each of the phase shift circuits
17
A to
17
D comprises a switch
17
S.
By switching the internal switches of the switch
17
S, a predetermined feed phase shift amount (to be described below) is supplied.
The phase controller
42
for individually controlling the switches
17
S of the respective phase shift circuits
17
A to
17
D is constituted by latches
43
A to
43
D respectively arranged for the phase shift circuits
17
A to
17
D.
The data distributor
41
of the driver unit
12
outputs control signals
41
A to
41
D to the latches
43
A to
43
D which constitute the phase controller
42
to give the phase controller
42
the phase shift amount of the radiating element
15
.
Therefore, the inputs D of the latches
43
A to
43
D receive the control signals
41
A to
41
D, respectively.
The inputs CLK of the latches
43
A to
43
D receive the trigger signal Trg output from the control unit
11
.
The latches
43
A to
43
D latch the control signals
41
A to
41
D at the leading (or trailing) edge of the trigger signal Trg, and output the outputs Q to the switches
17
S of the corresponding phase shift circuits
17
A to
17
D.
The ON/OFF states of the switches
17
S of the phase shift circuits
17
A to
17
D are determined in accordance with the states of the latched control signals
41
A to
41
D.
In this fashion, the phase shift amounts of the phase shift circuits
17
A to
17
D are set to set the total phase shift amount of the phase shifter
17
. Accordingly, a predetermined feed phase shift amount is given to an RF signal propagating through the strip line
16
.
Note that the switches
17
S may be sequentially switched by always outputting the trigger signal Trg, i.e., always keeping the trigger signal Trg at high level (or low level). In this case, the entire phase shifter
17
is not simultaneously switched but is partially switched, which avoids a hit of a radiation beam.
If the output voltages or currents of the latches
43
A to
43
D are not high enough to drive the switches
17
S, voltage amplifiers or current amplifiers may be arranged on the output sides of the latches
43
A to
43
D.
The substrate arrangement of the phased array antenna according to this embodiment will be described next with reference to FIG.
4
.
FIG. 4
is a view for explaining the multilayered substrate unit
2
, which shows perspective views of layers and schematic views of sections.
The layers are patterned by photolithography, etching, or printing and stacked and integrated into a multilayer.
The stacking order of the respective layers is not necessarily limited to the one shown in FIG.
4
. Even if the stacking order partially changes due to deletion or addition depending on the electrical/mechanical requirement, the present invention is effective.
A branch-like strip line
23
for distributing RF signals applied from the feeder
13
is formed on a distribution/synthesis layer
39
.
The strip lines
23
can use a tournament scheme in which two branches are repeated or a series distribution scheme for gradually branching the main line in comb-like teeth.
A dielectric layer
38
A and a ground layer
39
A made of a conductor are added outside the distribution/synthesis layer
39
in accordance with a mechanical design condition such a mechanical strength or an electrical design condition such as unnecessary radiation suppression.
A coupling layer
37
(second coupling layer) is formed above the distribution/synthesis layer
39
through a dielectric layer
38
.
The coupling layer
37
is comprised of a conductive pattern in which holes, i.e., coupling slots
22
are formed on a ground plane.
A phase control layer
35
is formed above the coupling layer
37
through a dielectric layer
36
.
The strip line
16
, the phase shifters
17
, and the control signal lines
53
for connecting the phase shifters
17
to the driver units
12
are formed on the phase control layer
35
, and a large number of them (the total number of phase shifters
17
is about 5,000 in the example as described above) are simultaneously formed by photolithography or etching.
A coupling layer
33
(first coupling layer) having coupling slots
21
as in the coupling layer
37
is formed above the phase control layer
35
through a dielectric layer
34
.
A radiating element layer
31
having the radiating elements
15
is formed above the coupling layer
33
through a dielectric layer
32
.
A passive element layer
31
A having passive elements
15
A is formed above the radiating element layer
31
through a dielectric layer
31
B.
However, the passive elements
15
A are added to widen the band, and may be arranged as needed.
Each of the dielectric layers
31
B,
32
,
38
, and
38
A is made of a material having low relative dielectric constant of about 1 to 4, e.g., a printed board, glass substrate, or foaming material. These dielectric layers may be spaces (air layers).
As the dielectric layer
36
, a semiconductor substrate (silicon, gallium arsenide, or the like) as well as a glass substrate can be used. Alternatively, a circuit board such as a ceramics board or a printed board may be used.
In particular, since the switches of the phase shifter
17
are simultaneously formed on the phase control layer
35
as described above, the dielectric layer
34
may be made of a space (air layer).
For the sake of descriptive simplicity, the respective layers constructing the multilayered substrate portion
2
are separately described in FIG.
4
. However, a layer adjacent to each of the dielectric layers
31
B,
32
,
34
,
36
,
38
, and
38
A, e.g., the radiating element layer
31
or dielectric layer
32
is realized by patterning it on one or two sides of the dielectric layer.
The aforementioned dielectric layer is not made of a single material and may have an arrangement in which a plurality of materials are stacked.
In the antenna having the multilayered structure described above, the RF signal from the feeder
13
(not shown in
FIG. 4
) propagates from the strip line
23
of the distribution/synthesis layer
39
to the strip lines of the phase control layer
35
via the coupling slots
22
of the coupling layer
37
.
The RF signal is then given a predetermined feed phase shift amount in the phase shifter
17
and propagates to the radiating elements
15
of the radiating element layer
31
via the coupling slots
21
of the coupling layer
33
to radiate from each radiating element
15
to a predetermined beam direction.
In this manner, in the present invention, the radiating elements
15
and the phase shifters
17
are individually formed on the radiating element layer
31
and the phase control layer
35
, respectively, and both layers are coupled by the coupling layer
33
to form the multilayered structure as a whole.
In addition, the distribution/synthesis unit
14
is individually formed on the distribution/synthesis layer
39
, and the phase control layer
35
and distribution/synthesis layer
39
are coupled by the coupling layer
37
to form the multilayered structure as a whole.
This reduces the area, of the phase control layer
35
, which is to be occupied by the radiating elements
15
and distribution/synthesis unit
14
even if the number of radiating elements
15
increases in order to improve the gain.
Accordingly, one phase shifter
17
is formed in a relatively small area. For this reason, e.g., for the RF signal of about 30 GHz, the radiating elements
15
can be arranged at an optimum interval of around 5 mm, thereby realizing the high-gain phased array antenna applicable to an RF band.
In addition, an angle in which the grating lobe is generated is made large by realizing the optimum element interval, thereby scanning a beam within a wide range centered on the front direction of the antenna.
In the phase control layer
35
, the switches
17
S used in the phase shift circuits
17
A to
17
D are simultaneously formed together with the wiring patterns (i.e., the first strip line
16
, second strip line, and control signal lines
53
) of the phase control layer
35
. Thus, as compared to the case in which the circuit components are individually mounted as in the prior art, the number of separately mounted components, the number of connections, and the number of assembling processes can be decreased, thereby reducing the manufacturing cost of the whole phased array antenna.
As each strip line
16
used in the present invention and the strip line used in each phase shifter
17
, a triplet type, coplanar type, slot type, or the like as well as a microstrip type distributed constant line can be used.
As the radiating element
15
, a printed dipole antenna, slot antenna, aperture element or the like as well as a patch antenna can be used.
In particular, the opening of the coupling slot
21
of the coupling layer
33
is made large, which is usable as a slot antenna. In this case, the coupling layer
33
also serves as the radiating element layer
31
, and the radiating element layer
31
and passive element layer
31
A can be omitted.
In place of the coupling slots
21
, conductive feed pins for connecting the strip lines
16
of the phase control layer
35
and the radiating elements
15
may be used to couple the RF signals.
Further, in place of the coupling slots
22
, conductive feed pins projecting from the strip lines of the phase control layer
35
to the dielectric layer
38
through holes formed in the coupling layer
37
may be used to couple the RF signals.
The same function as that of the distribution/synthesis layer
39
can also be realized even if a radial waveguide is used.
FIG. 5
is a view for explaining the arrangement of the present invention when using the radial waveguide.
In this case, a distribution/synthesis function is realized by a dielectric layer
38
, ground layer
39
A, and probe
25
of a multilayered substrate unit
2
shown in
FIG. 5
, and a distribution/synthesis layer
39
required in
FIG. 4
can be omitted.
In this case, the dielectric layer
38
is also made of a printed board, glass substrate, foaming agent, or space (air layer). As the ground layer
39
A, the copper foil on a printed board may be directly used, or a metal plate or a metal enclosure for enclosing all the side surfaces of the dielectric
38
may be separately arranged.
The present invention can also be applied to a space-fed phased array antenna.
FIG. 6
shows the arrangement of a reflection-type space-fed phased array antenna as an example.
A phased array antenna
1
shown in
FIG. 6
is made up of a feeder
13
, a radiation feeder
27
having a primary radiation unit
26
, a multilayered substrate unit
2
, and a control unit
11
(not shown). In this structure, the multilayered substrate unit
2
has a structure different from that shown in
FIG. 4
, which is constructed by a radiating element layer
31
, dielectric layer
32
, coupling layer
33
, dielectric layer
34
, and phase control layer
35
.
The function of the distribution/synthesis unit
14
shown in
FIG. 1
is realized by the primary radiation unit
26
so that a distribution/synthesis layer
39
is excluded from the multilayered substrate unit
2
.
In the phased array antenna
1
, an RF signal radiated from the radiation feeder
27
is temporarily received by each radiating element
15
on the radiating element layer
31
, and is coupled to each phase shifter
17
on the phase control layer
35
via the coupling layer
33
. After the phase of the RF signal is controlled by each phase shifter
17
, the RF signal propagates to each radiating element
15
again via the coupling layer
33
, and radiates from each radiating element
15
in the predetermined beam direction.
The present invention is effective even for the space-fed phased array antenna as described above which includes no distribution/synthesis layer
39
in the multilayered substrate unit
2
.
An example of the arrangement of the phase control layer
35
will be explained next with reference to FIG.
7
.
FIG. 7
is an explanatory view schematically showing an arrangement on the phase control layer
35
.
In a multilayered structure region on the phase control layer
35
, many phase shifters
17
are arranged in an array, and the wiring patterns of the control signal lines
53
are formed.
The plurality of driver units
12
each made up of a flip chip
51
are arranged in a region on the phase control layer
35
except for the multilayered structure region.
The flip chip
51
is a chip for bonding by using a connection terminal formed on a chip or board (i.e., for face-down bonding) without any lead wire such as a wire lead or a beam lead.
If the flip chip
51
is mounted by a bump scheme, bumps
52
are formed on the chip electrodes as connection terminals to connect to the wiring lines of the phase control layer
35
directory or through an anisotropy conductive sheet.
If the driver unit
12
is made up of the flip chip
51
, the bumps
52
are formed on the input electrodes of the data distributor
11
i
, the common electrode of the inputs CLK of latches
43
which constitute each phase controller
42
, and the electrodes of the outputs Q of the latches
43
.
In particular, the bumps
52
serving as the outputs Q of the latches
43
are individually connected to one of the phase shift circuits
17
A to
17
D of the phase shifter
17
by the control signal lines
53
formed on the phase control layer
35
.
Since the bumps
52
are formed not only around the chip but also on the entire surface of the chip, the chip size does not always increase even if the number of electrodes increases, thereby increase the packaging density of the IC.
For this purpose, even if, an increase in number of the radiating elements
15
increases the total number of bits of the phase shifter
17
to be controlled in order to improve the gain of an antenna, the driver unit
12
for driving the phase shifter
17
is comprised of the flip chip
51
, thereby suppressing an increase in size of the phased array antenna.
In addition, since the number of chips mounted on the phase control layer
35
can be decreased, a time required for arranging the chips at predetermined positions can be reduced, thereby suppressing an increase in manufacturing lead time.
Assume that, an example, in arranging the phased array antenna, the number of radiating elements
15
is set at 5,000 to obtain the gain of 36 dBi, and each phase shift circuit used in each phase shifter
17
is made up of 4 bits to obtain many beam scanning steps. In this case, total number of phase shift circuit bits is 20,000.
In this case, the chips corresponding to the 20,000 terminals are required for constructing the driver units
12
. However, all the phase shifters
17
can be driven by using the ten flip chips
51
each having 2,000 terminals.
The flip chips
51
are arranged on the two sides of the phase control layer
35
in the column direction.
The flip chips
51
on the left side control the left half of the phase shifters
17
arranged in the row direction while the flip chips
51
on the right side control the right half of the phase shifters
17
arranged in the row direction.
The phase control layer
35
has a two-layered structure, and the control signal line
53
for connecting the bumps
52
of the flip chip
51
to the respective phase shift circuits
17
A to
17
D are separately wired on the two layers of the phase control layer
35
.
The control signal lines
53
formed on a layer different from the flip chips
51
or the phase shift circuits
17
A to
17
D are connected to the flip chips
51
or the phase shift circuits
17
A to
17
D through via holes (electrical connecting holes) formed in a board.
With this structure, the maximum width of the bundle of the control signal lines
53
(see
FIGS. 13
to
17
) is made small, thereby reducing the area of the phase control layer
35
which is to be prepared for the control signal lines
53
.
This makes the phased array antenna small and decreases the intervals between the radiating elements
15
, thereby increasing the radiation beam range.
If the number of control signal lines
53
is small, or the width of each control signal line
53
is made small, the phase control layer
35
is not required to have the multilayered structure, and all the control signal lines
53
can be wired on the single layer.
In this example, the flip chip
51
in the bump scheme has been explained. However, bumps may be formed on a board on which the flip chips
51
is to be mounted (the phase control layer
35
in this case) in place of forming the bumps
52
on the chip, and the flip chips
51
are mounted as in the manner described above.
A structure of the switch
17
S will be described with reference to
FIG. 8
while using an example of practical sizes.
FIG. 8
is a perspective view showing the structure of the switch.
This switch
17
S is comprised of a micromachine switch for short-circuiting/releasing strip lines
62
and
63
by a contact (small contact)
64
. The “micromachine switch” means a small switch suitable for integration by a semiconductor device manufacturing process.
The strip lines
62
and
63
(about 1 μm thick) are formed on a substrate
61
at a small gap. The contact
64
(about 2 μm thick) is supported by a support member
65
above the gap so as to freely contact the strip lines
62
and
63
. The distance between the lower surface of the small contact
64
and the upper surfaces of the strip lines
62
and
63
is about 4 μm. The level of the upper surface of the small contact
64
from the upper surface of the substrate
61
, i.e., the height of the whole micromachine switch is about 7 μm.
A conductive electrode
66
(about 0.2 μm thick) is formed at the gap between the strip lines
62
and
63
on the substrate
61
. The height (thickness) of the electrode
66
is smaller than that of the strip lines
62
and
63
.
The operation of the switch will be explained.
The electrode
66
receives an output voltage (e.g., about 10 to 100 V) from a corresponding one of the driver circuits
19
A to
19
D.
When a positive output voltage is applied to the electrode
66
, positive charges are generated on the surface of the electrode
66
. At the same time, negative charges appear on the surface of the facing contact
64
(to be referred to as a lower surface hereinafter) by electrostatic induction, and are attracted to the strip lines
62
and
63
by the attraction force between the
Since the contact
64
is longer than the gap between the strip lines
62
and
63
, the contact
64
contacts both the strip lines
62
and
63
, and the strip lines
62
and
63
are electrically connected in a high-frequency manner through the contact
64
.
When application of the output voltage to the electrode
66
stops, the attraction force disappears, and the contact
64
returns to an original apart position by the support member
65
to release the strip lines
62
and
63
.
In the above description, the output voltage is applied to the electrode
66
without applying any voltage to the contact
64
. However, the operation may be reversed.
That is, the output voltage of the driver circuit may be applied to the contact
64
via the conductive support member
65
without applying any voltage to the electrode
66
. Even in this case, the same effects as those described above can be attained.
At least the lower surface of the contact
64
may be formed from a conductor so as to ohmic-contact the strip lines
62
and
63
. Alternatively, an insulating thin film may be formed on the lower surface of the conductive member so as to capacitively couple the strip lines
62
and
63
.
In the micromachine switch, the contact
64
is movable. When the phase control layer
35
is formed on a multilayered substrate, like a phased array antenna, a space for freely moving the contact
64
must be defined.
In this manner, since the micromachine switch is used as the switching element for controlling the feed phase, the power consumption at the semiconductor junction can be eliminated as compared with the use of a semiconductor device such as a PIN diode. This makes it possible to reduce the power consumption to about {fraction (1/10)}.
A formation means of circuit components of the phase shifter
17
incorporated in the phase control layer
35
, the strip line
16
, and the control signal line
53
will be described next.
FIGS. 9 and 10
show a case in which the control signal lines
53
(corresponding to wiring lines
220
and
221
) and the switch
17
S (micromachine switch in this case) are simultaneously formed by applying a semiconductor element manufacturing process, and particularly, by applying a wiring means by a thin film as an example of the means for forming a circuit component.
First, a glass substrate
201
whose surface is accurately polished to have flatness Ra=about 4 to 5 nm is prepared, and a photoresist is applied onto the glass substrate
201
.
The glass substrate
201
is patterned by known photolithography, and a resist pattern
202
having grooves
220
A at predetermined portions is formed on the glass substrate
201
, as shown in FIG.
9
(
a
).
As shown in FIG.
9
(
b
), a metal film
203
made of chromium, aluminum or the like is formed on the resist pattern
202
having the grooves
202
A by sputtering.
The resist pattern
202
is removed by a method, e.g., dissolving it in an organic solvent to selectively remove (lift off) the metal film
203
on the resist pattern
202
, thereby forming the wiring patterns
220
on the glass substrate
201
, as shown in FIG.
9
(
c
).
As shown in FIG.
9
(
d
), silicon oxide or the like is grown on the glass substrate
201
by sputtering so as to cover the wiring patterns
220
, thereby forming an insulating film
204
.
Then, as shown in FIG.
9
(
e
), a photoresist
205
is applied on the insulating film
204
and patterned by known photolithography, thereby forming, as shown in FIG.
9
(
f
), a resist pattern
205
having grooves
221
A,
62
A,
63
A, and
66
A, and an openings (not shown). The grooves
221
A are formed at predetermined positions corresponding to wiring lines which are to be formed; the grooves
62
A and
63
A, at positions of the strip lines
62
and
63
, respectively; the groove
66
A, at a predetermined position corresponding to the electrode
66
; and the opening, at a position corresponding to a column portion (
65
A shown in FIG.
10
(
l
)) of the support member
65
of the switch
17
S.
As shown in FIG.
10
(
g
), a metal film
206
made of, e.g., chromium or aluminum is formed by sputtering on the resist pattern
205
so as to bury the grooves
62
A,
63
A,
66
A, and
221
A and the opening.
The resist pattern
205
is removed by dissolving it in the organic solvent so that, as shown in FIG.
10
(
h
), the wiring patterns
221
and the strip lines
62
and
63
of the switch
17
S, the electrode
66
, and the columnar electrode (not shown) of the support member
65
are simultaneously formed.
Next, as shown in FIG.
10
(
i
), a metal film
209
made of gold or the like is selectively grown on the strip lines
62
and
63
.
With this processing, the wiring resistance decreases to reduce the propagation loss in an RF band while an air gap is ensured between the contact
64
and the electrode
66
to avoid short-circuiting therebetween even if the contact
64
is displaced to a position where the strip lines
62
and
63
are electrically connected in a high-frequency manner.
As shown in FIG.
10
(
j
), polyimide or the like is applied, dried, and harden on the entire surface of the substrate
201
to form a sacrificial layer
211
about 5 to 6 μm thick.
An opening (not shown) is formed at the position, where the column of the support member
65
of the switch
17
S is to be formed, by known photolithography and etching to form a column portion made of a metal so as to fill the opening with it.
Then, as shown in FIG.
10
(
k
), the arm portion of the support member
65
and the contact
64
are formed by lift-off at a position across the column portion and a portion above the strip lines
62
and
63
.
With this processing, the arm portion of the support member
65
and the contact
64
are electrically connected to the column portion of the support member
65
.
As shown in FIG.
10
(
l
), only the sacrificial layer
211
is selectively removed by dry-etching using oxygen gas plasma.
With this processing, the aforementioned micromachine switch (switch
17
S) (
FIG. 8
) and the wiring patterns
220
and
221
of the control signal lines
53
are simultaneously formed on the glass substrate
201
, i.e., the phase control layer
35
.
The above example has described the means for simultaneously forming the wiring patterns
220
and
221
and switch
17
S on the glass substrate. However, the means for forming the circuit components of the phase shifter
17
of the present invention is not limited to this, and the switch
17
S can be separately formed after forming the wiring patterns of the control signal lines
53
on the glass substrate in advance.
A ceramics board made of aluminum or the like or a semiconductor substrate can also be used in place of the glass substrate
201
.
As described above, in the present invention, the circuit components of the phase shifter
17
, the strip line
16
, and the control signal lines
53
are simultaneously formed on a single surface of the phase control layer
35
in the single process by using a semiconductor device manufacturing process. This reduces the number of components to be individually mounted and the number of connections, thereby reducing the number of assembling processes. As a result, the manufacturing cost of the whole phased array antenna can be greatly reduced.
A method of mounting the switch
17
S used in the phase shifter
17
will be described next with reference to FIG.
11
.
In the present invention, the many switches
17
S of the phase shifter
17
are simultaneously formed on the single substrate in the phase control layer
35
which is stacked in the multilayered structure.
FIG. 11
shows views for explaining an example of mounting the switch
17
S by exemplifying a case wherein a mounting space for the switch
17
S is formed by a spacer serving as a separate component, in which FIG.
11
(
a
) shows a case wherein a space is ensured above the switches
17
S, and FIG.
11
(
b
) shows a case wherein a space is ensured below the switches
17
S.
In FIG.
11
(
a
), the phase control layer
35
is formed on the dielectric layer
36
, and the switches
17
S used in the phase shifter
17
(micromachine switches in this case) is formed at once on the phase control layer
35
.
As the dielectric layer
36
, a semiconductor substrate (silicon, gallium arsenide, or the like) as well as the glass substrate (relative dielectric constant: about 4 to 8) can be used. Alternatively, a circuit board such as a ceramics board or a printed board may be used.
The thin film of the phase control layer
35
is formed by vacuum deposition or sputtering, and the pattern is formed by using a metal mask or photoetching.
As described above, when the switch
17
S having a movable portion such as the contact
64
of the micromachine switch is used, a space for mounting the switch
17
S need be ensured.
In this example, the mounting space has a space
34
S (internal space) formed between the phase control layer
35
and coupling layer
33
, and the space
34
S is formed by forming a spacer
34
A serving as a separate component.
In this case, the spacer
34
A may be arranged below the coupling slot
21
. With this arrangement, a space immediately under the coupling slot
21
, which is generally an unused region, also serves as a region in which the spacer
34
A is arranged, thereby reducing the area occupied by the spacer
34
A.
As the spacer
34
A, a material having high relative dielectric constant of about 5 to 30 such as alumina may be used and arranged under the coupling slot
21
. Thus, the coupling slot
21
and the strip line
24
on the phase control layer
35
are efficiently coupled in a high-frequency manner.
Although not shown in
FIG. 11
, the spacer
34
A may be formed from a conductor and arranged on the upper portion of a via hole (electrical connecting hole) separately formed in the dielectric layer
36
, and may be electrically connected to ground patterns, e.g., the conductive patterns of the coupling layers
33
and
37
.
In FIG.
11
(
b
), as compared to FIG.
11
(
a
) described above, the stacking order of the dielectric layer
36
, phase control layer
35
, and dielectric layer
34
is reversed.
More specifically, the upper side of the dielectric layer
36
closely contacts the coupling layer
33
, the spacer
34
A is formed between the phase control layer
35
on the lower side of the dielectric layer
36
and coupling layer
37
, and the dielectric layer
34
is formed by the space
34
S.
Therefore, the micromachine switch of the switch
17
S has a shape enough to ensure a space
34
S below the phase control layer
35
.
Another method of mounting the switch
17
S used in the phase shifter
17
will be described next with reference to FIG.
12
.
FIG. 12
shows views for explaining another example of mounting the switch
17
S, in which a mounting space for the switch
17
S is formed by various types of members.
FIG.
12
(
a
) shows a case wherein the space
34
S serving as the mounting space for the switch
17
S is formed by a dielectric film
34
C.
In this case, after a dielectric film is added on the sacrificial layer
211
used in forming the switch
17
S, the additive dielectric film and a part of the sacrificial layer
211
are selectively removed, thereby forming the dielectric film
34
C having a thickness larger than the height of the switch
17
S.
By using a photosensitive adhesive as the dielectric film
34
C, it can also serve as an adhesive in the sequential substrate stacking process.
As will be described later in Example 3, the dielectric film
34
C may be made thin, and the height required for the dielectric layer
34
may be made up for a substrate
34
D (not shown in FIG.
12
).
FIG.
12
(
b
) shows a case wherein the space
34
S serving as the mounting space for the switch
17
S is formed by forming the wiring pattern conductor on the phase control layer
35
thick. In this case, if the switch
17
S has, e.g., the height of 7 μm as described above, the conductive may have the thickness of about 10 μm.
In a method of forming the wiring pattern conductor thick, the switch
17
S is protected and plated thick with a metal by electrolytic plating or the like.
As the wiring pattern conductor, the strip line
16
having a relatively large width or a spacer-dedicated wiring pattern having a large area is used which is separately formed, thereby obtaining a stable mounting space
34
S.
FIG.
12
(
c
) shows a case wherein the space
34
S serving as the mounting space for the switch
17
S is formed by using a substrate
34
E having a cavity (space)
34
F.
In this case, the cavity
34
F is formed in the substrate
34
E so as to correspond to the position of the switch
17
S mounted on the phase control layer
35
.
The substrate
34
E is stacked between the phase control layer
35
and coupling layer
33
as the dielectric layer
34
.
As the substrate
34
E, a dielectric substrate having a low dielectric constant (relative dielectric constant: about 1 to 4) or a high dielectric constant (relative dielectric constant: about 5 to 30) is used in accordance with the design condition.
The cavity
34
F may be formed by cutting the surface of the substrate
34
E by machining. Alternatively, the cavity
34
F may be formed by forming a through hole by punching or the like.
After a photosensitive resin is applied on an organic substrate, the resin corresponding to the cavity
34
F may be removed by exposing and developing processes. Various types of the formation methods are usable.
EXAMPLES
Examples 1 to 5 (examples of arrangements for each radiating element) will be described below with reference to
FIGS. 13
to
17
, in which the present invention is applied to a 30-GHz phased array antenna.
A case wherein a phase shifter
17
is made up of four phase shift circuits
17
A to
17
D having different phase shift amounts of 22.5°, 45°, 90°, and 180° will be described below.
Assuming that micromachine switches are used as the switching elements of the phase shift circuits
17
A to
17
D.
Example 1 will be described first with reference to FIG.
13
.
FIG. 13
shows views of a circuit arrangement of Example 1, in which FIG.
13
(
a
) is a diagram showing a circuit arrangement in a phase shifter formation region, FIG.
13
(
b
) is a schematic view showing a multilayered structure, and FIG.
13
(
c
) is an enlarged view showing the arrangement of a control line layer portion
53
A in a phase control layer
35
.
A phase shifter formation region
18
is a region in which a phase shifter
17
arranged in correspondence with a radiating element
15
is formed on the phase control layer
35
, which is a substantially square (5 mm×5 mm), as shown in FIG.
13
(
a
).
In the phase shifter formation region
18
, a strip line
16
is formed to connect the upper portion of a coupling slot
22
to the lower portion of a coupling slot
21
.
Phase shift circuits for 22.5°, 45°, 90°, and 180° are arranged midway along the strip lines
16
.
Control signal lines
53
extending from a driver unit
12
to each phase shifter
17
arrayed in a predetermined direction (the row direction in
FIG. 7
) are closely arranged on one side portion of the region
18
, and are formed like a bundle.
Phase shifters
17
A to
17
D are simultaneously formed on one surface of a single substrate (glass substrate) as the phase control layer
35
.
The circular radiating element
15
(broken narrow line shown in FIG.
13
(
a
)) having a diameter of 2.5 mm to 4 mm is arranged on a radiating element layer
31
above the coupling slot
21
.
FIG.
13
(
b
) schematically shows the multilayered structure in Example 1, and the same reference numerals as in
FIG. 11
denote the same parts.
Note that FIG.
13
(
b
) schematically shows the multilayered structure, but does not show a specific section in FIG.
13
(
a
).
The multilayered structure of this example is obtained by sequentially stacking from the bottom to top in FIG.
13
(
b
), a ground layer
39
A, a dielectric layer
38
(1 mm thick) in which a radial waveguide is formed, a ground layer
37
, a dielectric layer
36
(0.2 mm thick), the phase control layer
35
, a dielectric layer
34
(0.2 mm thick), a ground layer
33
in which the coupling slot
21
is formed, a dielectric layer
32
(0.3 mm thick), the radiating element layer
31
, a dielectric layer
31
B (1 mm thick), and a passive element layer
31
A.
In this structure, the dielectric layer
34
between the phase control layer
35
and ground layer
33
has a space ensured by 0.2-mm thick spacers
34
A, and switches
17
S are formed at once on the phase control layer
35
.
In this case, the spacer
34
A may be arranged below the coupling slot
21
. With this arrangement, a space immediately under the coupling slot
21
, which generally an unused region, also serves as a region in which the spacer
34
A is arranged, thereby reducing the area occupied by the spacer
34
A.
In addition, if a material having high relative dielectric constant of about 5 to 30 such as alumina is used as the spacer
34
A, the coupling slots
21
and the strip lines
16
on the phase control layer
35
are efficiently coupled in a high-frequency manner.
As shown in FIG.
13
(
c
), the phase control layer
35
has a two-layered structure in which an insulating layer
35
C is formed on the dielectric layer
36
. The control signal lines
53
are separately wired on the layers
35
A and
35
B to connect the driver units
12
and the phase shift circuits
17
A to
17
D, respectively.
Assume that the following conditions are given:
the number of radiating elements (row×column): 72×72 elements
wiring line width/wiring line interval (L/S): 4/4 μm
In this case, when ½ phase shifters
17
on each row are controlled by the same driving unit
12
, and control signal lines
58
equal in number to the layers
35
A and
35
B are to be formed, the width of the wiring bundle of the control signal lines
53
is given by:
8 μm×36 elements×4 bits/2 layers=0.58 mm
If the wiring line bundle has the width of around 0.58 mm, this wiring line bundle can be formed, within the region having 5 mm square, together with the 4-bit phase shifter coping with an RF signal having 30 GHz. For this reason, the interval between the radiating elements
15
can be set to 5 mm, thereby realizing the high-frequency (30 GHz) high-gain (36 dBi) phased array antenna without decreasing a beam scanning range.
Example 2 of the present invention will be described below with reference to FIG.
14
.
FIG. 14
shows views of a circuit arrangement of Example 2, in which FIG.
14
(
a
) is a diagram showing a circuit arrangement in a phase shifter formation region, FIG.
14
(
b
) is a schematic view showing a multilayered structure, and FIG.
14
(
c
) is an enlarged view showing the arrangement of a control line layer portion
53
A in a phase control layer
35
.
In this example, as a spacer forming a dielectric layer
34
, a spacer
34
B made of a conductor is used in place of a spacer
34
A having high dielectric constant.
In this case, the conductive spacer
34
B is arranged at a position of a via hole (connection hole)
36
A formed on the dielectric layer
36
, in which ground patterns, e.g., ground patterns of a coupling layer
37
and a coupling layer
33
are electrically connected to each other.
With this structure, an inter-ground-plate unnecessary mode (a parallel-plate mode) can be suppressed without individually forming any means which couples ground potentials with each other.
Example 3 of the present invention will be described below with reference to FIG.
15
.
FIG. 15
shows views of a circuit arrangement of Example 3, in which FIG.
15
(
a
) is a diagram showing a circuit arrangement in a phase shifter formation region, FIG.
15
(
b
) is a schematic view showing a multilayered structure, and FIG.
15
(
c
) is an enlarged view showing the arrangement of a control line layer portion
53
A in a phase control layer
35
.
In this structure, as shown in FIG.
12
(
a
), a space serving as a mounting space for switches
17
S is ensured by a dielectric film
34
B.
In particular, a dielectric layer
34
is made up of only a dielectric film
34
C in FIG.
12
(
a
). In Example 3, a substrate
34
D is inserted between the dielectric film
34
C and a coupling layer
33
.
When the necessary distance between the phase control layer
35
and the coupling layer
33
is considerably larger than the height of the switch
17
S, a dielectric layer
34
portion above the height of the space for receiving the switch
17
S is constructed by the substrate
34
D.
Assuming that, for example, the dielectric layer
34
needs a thickness of 0.2 mm, and the switch
17
s
has the height of about 7 μm as described above. In this case, the dielectric layer
34
C (e.g., a polyimide film) may have a thickness of about 10 μm, and the remaining height of 0.19 mm is compensated by the substrate
34
D.
With this structure, the dielectric film
34
C is suppressed thin, thereby easily forming the dielectric film
34
C.
A dielectric (e.g., relative dielectric constant=5 to 30) is used as the substrate
34
D so that an RF signal from a strip line
16
on the phase control layer
35
is efficiently coupled with a radiating element
15
via a coupling slot
21
.
Example 4 of the present invention will be described below with reference to FIG.
16
.
FIG. 16
shows views of a circuit arrangement of Example 4, in which FIG.
16
(
a
) is a diagram showing a circuit arrangement in a phase shifter formation region, FIG.
16
(
b
) is a schematic view showing a multilayered structure, and FIG.
16
(
c
) is an enlarged view showing the arrangement of a control line layer portion
53
A in a phase control layer
35
.
In Example 4, as shown in FIG.
12
(
b
), a space
34
S serving as a mounting space for switches
17
S is ensured by the thickness of the wiring pattern of the phase control layer
35
.
In this structure, a wiring pattern
16
B which is a part of a strip line
16
is formed by plating it thick to have a thickness larger than the height of the switch
17
S.
A substrate
34
D is inserted between the thick-film wiring pattern
16
B and a coupling layer
33
.
A material having a high dielectric constant (e.g., relative dielectric constant=5 to 30) is used as the substrate
34
D so that an RF signal from the strip line
16
of the phase control layer
35
is efficiently coupled with a radiating element
15
via a coupling slot
21
.
Example 5 of the present invention will be described below with reference to FIG.
17
.
FIG. 17
shows views of a circuit arrangement of Example 5, in which FIG.
17
(
a
) is a diagram showing a circuit arrangement in a phase shifter formation region, FIG.
17
(
b
) is a schematic view showing a multilayered structure, and FIG.
17
(
c
) is an enlarged view showing the arrangement of a control line layer portion
53
A in a phase control layer
35
.
In Example 5, as shown in FIG.
12
(
c
), a space
34
S serving as a mounting space for switches
17
S is ensured by a substrate
34
E having a cavity
34
F.
In this structure, the cavity (space)
34
F is formed at the position, in the substrate
34
E, where the switch
17
S is mounted on the phase control layer
35
, and the switch
17
S is housed in the cavity
34
F when the substrates are tightly bonded.
A material having a high dielectric constant (e.g., relative dielectric constant=5 to 30) is used as the substrate
34
E so that an RF signal from a strip line
16
of the phase control layer
35
is efficiently coupled with a radiating element
15
via a coupling slot
21
.
As a method of forming the cavity
34
F in the substrate
34
E, machining in which the surface of the substrate
34
E is cut using a router or in which a through hole is formed by punching may be used.
Alternatively, after a photosensitive resin is applied on an organic substrate, the resin corresponding to the cavity
34
F may be removed by exposing and developing processes. Various types of the formation methods are usable.
Examples 1 to 5 have exemplified the case wherein the space
34
S serving as a space in which the switch
17
s
is mounted is formed above the phase control layer
35
. As in FIG.
11
(
b
), however, the space
34
S may be formed below the phase control layer
35
.
As described above, the case wherein a radial waveguide is adopted as a distribution/synthesis unit
14
is described with reference to
FIGS. 13
to
17
. However, the form shown in
FIG. 4
, i.e., a distribution/synthesis layer
39
using the branch strip line may also be used.
In addition, as described above, the present invention can also be applied to a stacking order different from that in the examples in
FIGS. 13
to
17
. For example, the multilayered structure is obtained by sequentially stacking from the bottom to top, a phase control layer
35
, dielectric layer
36
, coupling layer
37
, dielectric layer
38
A, distribution/synthesis layer
39
, dielectric layer
38
, coupling layer
33
, dielectric layer
32
, and radiating element layer
31
, and the distribution/synthesis layer
39
and the phase control layer
35
can also be arranged as innermost and outermost layers, respectively.
In this case, as a means for coupling RF signals between the layers in this structure, for example, a feed pin extending through a hole formed in the dielectric layer
37
may connect the phase control layer
35
to the distribution/synthesis layer
39
in a high-frequency manner, and a feed pin extending along the coupling layer
37
and coupling layer
33
may also connect the phase control layer
35
to a radiating element
15
.
In this manner, the phase control layer
35
is arranged as the outermost layer so that the stacked structure can be obtained regardless of the height of a phase shifter
17
.
In addition, as the form shown in
FIG. 6
, the radiation feeder
27
and the multilayered substrate unit
2
may be separately formed to use a space-fed system. By using this system, a layer functioning as the distribution/synthesis unit
14
(the distribution/synthesis layer
27
shown in
FIG. 2
or the radial waveguide in Examples shown in
FIGS. 13
to
17
) can be excluded from the multilayered substrate unit
2
.
INDUSTRIAL APPLICABILITY
The phased array antenna of the present invention is a high-gain antenna applicable to an RF band, and is effective for a satellite tracking on-vehicle antenna or satellite borne antenna used for satellite communication.
Claims
- 1. A phased array antenna used to transmit/receive an RF signal such as a microwave and milliwave to adjust a beam direction by controlling a phase of the RF signal transmitted/received by each radiation element, characterized by comprisinga first multilayered structure made up of at least radiation element means on which a large number of radiation elements are arranged, and phase control means on which a large number of phase controllers for controlling the phase of the RF signal transmitted/received to/from each radiation element are mounted, wherein each phase controller includes a plurality of driver means for outputting control signals to give a predetermined phase shift amount for each radiating element and a plurality of phase shift means for receiving the control signals to control a phase of each radiating element, the phase shift means being simultaneously formed on a substrate of the phase control means, and the phase control means has an internal space having a predetermined height on an internal layer surface mounted with the phase controllers.
- 2. A phased array antenna according to claim 1, characterized in that said phased array antenna has a first coupling layer arranged between the phase control means and the radiating element means to couple the RF signals.
- 3. A phased array antenna used to transmit/receive an RF signal such as a microwave and milliwave to adjust a beam direction by controlling a phase of the RF signal transmitted/received by each radiation element, characterized by comprisinga first multilayered structure in which phase control means on which each phase controller for controlling the phase of the RF signal transmitted/received to/from each radiating element is mounted, a first coupling layer for coupling the RF signals, radiating element means on which a large number of radiating elements are arranged, and a passive element layer are sequentially stacked, wherein each phase controller includes a plurality of driver means for outputting control signals to give a predetermined phase shift amount for each radiating element and a plurality of phase shift means for receiving the control signals to control a phase of each radiating element, the phase shift means being simultaneously formed on a substrate of the phase control means, and the phase control means has an internal space having a predetermined height on an internal layer surface mounted with the phase controllers.
- 4. A phased array antenna according to claim 1, characterized in that the phase control means has a second multilayered structure having a plurality of wiring layers.
- 5. A phased array antenna according to claim 3, characterized in that each dielectric layer is formed between the respective layers constructing said first multilayered structure.
- 6. A phased array antenna according to claim 1, characterized in that said phased array antenna further comprises a distribution/synthesis unit for distributing a transmission signal to each phase controller and synthesizing a reception signal from each phase controller.
- 7. A phased array antenna according to claim 1, characterized in that each phase shift means comprises a plurality of phase shift circuits for receiving outputs from the driver means and capable of making strip lines, each having a length corresponding to a different phase shift amount, switch by using RF switches.
- 8. A phased array antenna according to claim 1, characterized in that each driver means comprises a data distributor for receiving control data from a control unit to distribute the control data for predetermined radiating elements, and a plurality of phase controllers for latching and outputting outputs from the data distributor as the control signals on the basis of a trigger signal.
- 9. A phased array antenna according to claim 8, characterized in that the trigger signal is a pulse signal.
- 10. A phased array antenna according to claim 8, characterized in that the trigger signal is always output to the phase controller.
- 11. A phased array antenna according to claim 1, characterized in that the driver means uses a flip chip.
- 12. A phased array antenna according to claim 7, characterized in that the RF switch is comprised of a micromachine switch for electrically connecting/releasing a strip line to/from another strip line through a contact supported apart from the strip line by electrically or magnetically operating the contact.
- 13. A phased array antenna according to claim 1, characterized in that the radiating element is a patch or slot antenna.
- 14. A phased array antenna according to claim 6, characterized in that said distribution/synthesis unit is comprised of a distribution/synthesis layer having a branch circuit using a strip line or a radial waveguide using a metal enclosure with an internal space, and the distribution/synthesis layer is coupled to the phase control means via a second coupling layer.
- 15. A phased array antenna according to claim 6, characterized in that the distribution/synthesis unit is comprised of a primary radiation unit for performing space feeding.
- 16. A phased array antenna according to claim 2, characterized in that the first coupling layer couples layers by using a coupling slot or conductive feed pin.
- 17. A phased array antenna according to claim 14, characterized in that the second coupling layer couples layers by using a coupling slot or conductive feed pin.
- 18. A phased array antenna according to claim 5, characterized in that the dielectric layer is made of glass.
- 19. A phased array antenna according to claim 12, characterized in that the predetermined height is made larger than a maximum height of the contact from a bottom surface of the micromachine switch.
- 20. A phased array antenna according to claim 1, characterized in that the predetermined height is ensured by a dielectric spacer formed on the phase control means.
- 21. A phased array antenna according to claim 20, characterized in that said phased array antenna comprises a first coupling layer arranged between the phase control means and the radiating element means to couple the RF signals, and the dielectric spacer is formed below a coupling slot of the first coupling layer.
- 22. A phased array antenna according to claim 1, characterized in that the predetermined height is ensured by a conductive spacer formed on the phase control means.
- 23. A phased array antenna according to claim 10, characterized in that the predetermined height is ensured by a sacrificial layer used to form the micromachine switch and a dielectric film formed on the sacrificial layer.
- 24. A phased array antenna according to claim 19, characterized in that the predetermined height is ensured by forming thick a wiring pattern conductor except for a portion brought into contact with a contact of the micromachine switch.
- 25. A phased array antenna according to claim 1, characterized in that the predetermined height is ensured by a cavity formed by partially removing a dielectric layer formed on the phase control means.
- 26. A phased array antenna according to claim 1, characterized in that the driver means are arranged on two sides of the phase control means.
- 27. A method of manufacturing a phased array antenna used to transmit/receive an RF signal such as a microwave and milliwave to adjust a beam direction by controlling a phase of the RF signal transmitted/received by each radiation element, characterized by comprising the step of:patterning, by photolithography and etching, at least radiating element means on which a large number of radiation elements are arranged and phase control means on which parts of phase controllers for controlling the phase of the RF signal transmitted/received to/from each radiation element are simultaneously formed, respectively; stacking the patterned layers in a predetermined order; and bonding the stacked layers to each other.
- 28. A method of manufacturing a phased array antenna according to claim 27, characterized in that each phase controller includes a plurality of driver means for outputting control signals to give a predetermined phase shift amount for each radiating element and a plurality of phase shift means for receiving the control signals to control a phase shift of each radiating element.
- 29. A method of manufacturing a phased array antenna according to claim 28, characterized in that the driver means include a plurality of flip chips, and each phase shift means comprises a plurality of phase shift circuits for receiving outputs from the driver means and capable of making strip lines, each having a length corresponding to a different phase shift amount, switch by using RF switches.
- 30. A method of manufacturing a phased array antenna according to claim 29, characterized in that the RF switch is comprised of a micromachine switch for electrically connecting/releasing a strip line to/from another strip line through a contact supported apart from the strip line by electrically or magnetically operating the contact.
- 31. A method of manufacturing a phased array antenna according to claim 27, characterized in that the phase control means has the step of forming the strip lines of the micromachine switch and an electrode formed below the contact,the step of selectively growing an electrolytic-plating portion on the strip line, the step of forming a sacrificial layer, and the step of forming the contact on the sacrificial layer.
- 32. A method of manufacturing a phased array antenna according to claim 31, characterized in that the sacrificial layer is made of polyimide.
- 33. A method of manufacturing a phased array antenna according to claim 31, characterized in that the substrate is glass.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10-368067 |
Dec 1998 |
JP |
|
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/JP99/06514 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO00/39891 |
7/6/2000 |
WO |
A |
US Referenced Citations (9)
Foreign Referenced Citations (6)
Number |
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2241375 |
Dec 1998 |
CA |
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Aug 1978 |
JP |
1-290301 |
Nov 1989 |
JP |
5-91016 |
Dec 1993 |
JP |
6-267926 |
Sep 1994 |
JP |
11-74717 |
Mar 1999 |
JP |