Patent Application
20210210864
The present disclosure relates to a radio communication apparatus. The present disclosure relates to, for example, a radio communication apparatus suitable for transmitting and receiving high-quality RF (Radio Frequency) signals.
A phased array antenna includes at least a plurality of phase shifters for adjusting a phase of a reference RF signal to generate a plurality of RF signals, a control circuit for controlling phase shift amounts of the respective phase shifters, and a plurality of antennas for emitting the phase-adjusted plurality of RF signals into the air.
Recently, in a phased array antenna, it has been desired to integrally form an RF circuit and a plurality of antennas on one printed board. The RF circuit here includes a plurality of phase shifters and a control circuit for controlling the phase shift amounts of the phase shifters. By integrally forming the RF circuit and the plurality of antennas on one printed board, a cable and a waveguide for connecting the RF circuit to the plurality of antennas become unnecessary, so that the circuit size can be reduced and transmission loss of the RF signal in a transmission path can also be reduced.
In order to integrally form an RF circuit and a plurality of antennas on one printed board, planar antennas called patch antennas may be used as the plurality of antennas to form the antennas. However, the patch antenna has a problem that the bandwidth is narrow and the transmission loss of the RF signal in the transmission path is still large.
A solution to such a problem is disclosed in Patent Literature 1. Patent Literature 1 discloses a configuration of an antenna formed using a multilayer wiring board. The antenna having this configuration can transmit and receive an RF signal having a bandwidth wider than that of an RF signal transmitted and received by the patch antenna.
Patent Literature 1: Japanese Unexamined Patent Application Publication No. H11-239017
However, Patent Literature 1 does not disclose how an RF circuit integrally formed with antennas on one printed board is formed in detail. For this reason, there is a problem that the quality of the RF signal deteriorates due to a transmission loss of the RF signal in the transmission path depending on how the RF circuit is formed.
An object of the present disclosure is to provide a radio communication apparatus that solves the above problem.
An example aspect is a radio communication apparatus including: a printed board; an RF circuit formed on one surface of the printed board and configured to generate an RF signal; a first transmission line configured to transmit the RF signal; a second transmission line configured to transmit a signal different from the RF signal; and an antenna formed on another surface of the printed board and configured to emit the RF signal supplied from the RF circuit through the first transmission line. The antenna includes: a plurality of dielectric substrates layered on the other surface of the printed board; a metal film formed on surfaces of the plurality of dielectric substrates; and a through hole formed in the plurality of dielectric substrates. The first transmission line is disposed from the RF circuit to an area facing the through hole on the one surface of the printed board, and a part of the second transmission line is disposed between the plurality of layered dielectric substrates.
Another example aspect is a radio communication apparatus including: a printed board; an RF circuit formed on one surface of the printed board and configured to generate a plurality of RF signals; a plurality of first transmission lines configured to transmit a plurality of RF signals; a plurality of second transmission lines configured to transmit a plurality of signals different from the plurality of RF signals; and a plurality of antennas formed on another surface of the printed board and configured to emit the plurality of RF signals supplied from the RF circuit through the plurality of first transmission lines, respectively. Each of the plurality of antennas includes: a plurality of dielectric substrates layered on the other surface of the printed board; a metal film formed on surfaces of the plurality of dielectric substrates; and a through hole formed in the plurality of dielectric substrates. Each of the plurality of first transmission lines is disposed from the RF circuit to an area facing the through hole on the one surface of the printed board, and a part of each of the plurality of second transmission lines is disposed between any of the plurality of layered dielectric substrates.
According to the above example aspects, it is possible to provide a radio communication apparatus capable of transmitting and receiving a high-quality RF signal.
Hereinafter, example embodiments will be described with reference to the drawings. Since the drawings are simplified, the technical scope of the example embodiments should not be narrowly interpreted on the basis of the description of the drawings. The same elements are denoted by the same reference signs, and repeated descriptions are omitted.
The disclosure will be described by dividing it into a plurality of sections or example embodiments whenever circumstances require it for convenience in the following embodiments. However, unless otherwise particularly specified, these sections or embodiments are not irrelevant to one another. One section or example embodiment is related to modified example, applications, details, supplementary explanations, and the like of some or all of the other ones. When reference is made to the number of elements or the like (including the number of pieces, numerical values, quantity, range, etc.) in the following example embodiments, the number thereof is not limited to a specific number and may be greater than or less than or equal to the specific number unless otherwise particularly specified and definitely limited to the specific number in principle.
Further, in the following example embodiments, components (including operation steps, etc.) are not always essential unless otherwise particularly specified and considered to be definitely essential in principle. Similarly, when reference is made to the shapes, positional relations, or the like of the components or the like in the following example embodiments, they will include ones, for example, substantially approximate or similar in their shapes or the like unless otherwise particularly specified and considered not to be definitely so in principle. This is similarly applied even to the above-described number or the like (including the number of pieces, numerical values, quantity, range, etc.).
As shown in
The RF signal generation circuit 11 modulates a baseband signal or an intermediate signal thereof (IF signal) into a high frequency RF signal Si using a local signal (LO signal) from a local oscillator. The phase shifters 12_1 to 12_n adjust the phase of the RF signal S1 generated by the RF signal generation circuit 11 and outputs a plurality of RF signals S1_1 to S1_n, respectively. The control circuit 13 controls the respective phase shift amounts of the plurality of phase shifters 12_1 to 12_n. The plurality of RF signals S1_1 to S1_n are emitted into the air from antennas A_1 to A_n, respectively. By controlling the phases of the plurality of RF signals S1_1 to S1_n, the radio communication apparatus 1 can provide the RF signal S1 with directivity.
The RF signals S1_1 to S1_n transmitted and received through the antennas A_1 to A_n are millimeter waves of a specific band in a range of, for example, 26 GHz to 110 GHz. Specifically, the RF signals S1_1 to S1_n are millimeter waves in a band from 60 GHz to 90 GHz (E band). Alternatively, the RF signals S1_1 to S1_n are any of millimeter waves in the band from 26 GHz to 40 GHz (Ka band), millimeter waves in the band from 50 GHz to 70 GHz (V band), and millimeter waves in the band from 75 GHz to 110 GHz (W band). When the RF signals S1_1 to S1_n of such a high frequency band are transmitted and received, it is particularly important to reduce the transmission loss of the RF signals S1_1 to S1_n in the transmission lines from the RF circuit 10 to the plurality of antennas A_1 to A_n.
First, radio communication apparatuses 51 and 61 which have been studied in advance by the present inventor will be described before explaining a configuration of the radio communication apparatus 1 described above.
As shown in
In the radio communication apparatus 51, the RF circuit 10 and the antennas A_1 to A_n are integrally formed on one printed board 101. Then, in the radio communication apparatus 51, it becomes unnecessary to connect the RF circuit 10 to the antennas A_1 to A_n by a cable or a waveguide, so that the circuit size can be reduced, and the transmission loss in the transmission line can also be reduced.
The RF circuit 10 such as an MMIC (Monolithic Microwave Integrated Circuit) is provided in an RF circuit formation layer 301 on one main surface of the printed board 101. The transmission line W1 for transmitting the RF signal S1_1 is wired to the RF circuit formation layer 301. The transmission line W1 is wired in the RF circuit formation layer 301 from the RF circuit 10 to an area facing a through hole 207 of the antenna A_1. In other words, the transmission line W1 is wired in the RF circuit formation layer 301 from the RF circuit 10 to the through hole 207 of the antenna A_1 when the printed board 101 is viewed in the z-axis direction. Further, the transmission line W2 for transmitting signals other than the RF signal S1_1 such as an LO signal, an IF signal, and a power supply voltage is wired to the RF circuit formation layer 301.
The antenna A_1 composed of a plurality of dielectric substrates 202 to 205 and a metal film 206 is formed on the other main surface of the printed board 101.
More specifically, the plurality of dielectric substrates 202 to 205 are layered on the other main surface of the printed board 101. The plurality of dielectric substrates 202 to 205 may be glass substrates for general use or substrates made of the same material as that of the printed board 101.
Among the layered dielectric substrates 202 to 205, the through hole 207 serving as a waveguide is formed in the dielectric substrate 202 disposed adjacent to the printed board 101. In the dielectric substrates 203 to 205, a space area 208 continuous to the through hole 207 is formed. Further, the metal film 206 is formed by performing a plating treatment on the surfaces of the plurality of layered dielectric substrates 202 to 205. In the metal film 206, a metal film 206a formed between the printed board 101 and the dielectric substrate 202 forms a ground layer (hereinafter also referred to as a ground layer 206a) of the antenna A_1 and the RF circuit 10.
The RF signal S1_1 generated by the RF circuit 10 is supplied to the antenna A_1 through the transmission line W1. The RF signal S1_1 propagates through the through hole 207 serving as a waveguide and reaches the space area 208 of the antenna A_1, and then is emitted into the air.
The antennas A_2 to A_n (not shown) have the same cross-sectional structure as that of the antenna A_1, and thus the descriptions of the antennas A_2 to A_n will be omitted.
The antenna having the cross-sectional structure shown in
However, in the structure of the radio communication apparatus 51 shown in
Therefore, the present inventor has studied a radio communication apparatus 61.
As shown in
Specifically, the RF circuit formation layers 301 to 303 are provided on one main surface of the printed board 101. The RF circuit 10 is formed in the RF circuit formation layer 301. In the RF circuit formation layers 302 and 303, a part of the transmission line W1 for transmitting the RF signal S1_1 is wired through a via V1, and a part of the transmission line W2 for transmitting signals other than the RF signal S1_1 such as an LO signal, an IF signal and a power supply voltage is wired through a via V2.
In the structure of the radio communication apparatus 61 shown in
However, in the structure of the radio communication apparatus 61 shown in
Furthermore, in the structure of the radio communication apparatus 61 shown in
In order to address such an issue, the present inventor has found the radio communication apparatus 1 according to the first example embodiment that can transmit (or receive) a high-quality RF signal without increasing the number of layers of an RF circuit formation layer by forming a transmission line using a metal film between a plurality of dielectric substrates constituting an antenna.
As shown in
In the radio communication apparatus 1, the RF circuit 10 and the antennas A_1 to A_n are integrally formed on one printed board 101. Then, in the radio communication apparatus 1, it becomes unnecessary to connect the RF circuit 10 to the antennas A_1 to A_n by a cable or a waveguide, so that the circuit size can be reduced, and the transmission loss in the transmission line can also be reduced.
The RF circuit 10 such as an MMIC is provided in an RF circuit formation layer 301 provided on one main surface of a printed board 101. The transmission line W1 for transmitting the RF signal S1_1 is wired to the RF circuit formation layer 301. The transmission line W1 is wired in the RF circuit formation layer 301 from the RF circuit 10 to an area facing a through hole 207 of the antenna A_1.
In other words, the transmission line W1 is wired in the RF circuit formation layer 301 from the RF circuit 10 to the through hole 207 of the antenna A_1 when the printed board 101 is viewed in the z-axis direction. Further, a part of the transmission line W2 for transmitting signals other than the RF signal S1_1 such as an LO signal, an IF signal, and a power supply voltage is wired to the RF circuit formation layer 301.
The antenna A_1 composed of a plurality of dielectric substrates 201 to 205 and the metal film 206 is formed on the other main surface of the printed board 101.
More specifically, the plurality of dielectric substrates 201 to 205 are layered on the other main surface of the printed board 101. The plurality of dielectric substrates 201 to 205 may be glass substrates for general use or substrates made of the same material as that of the printed board 101.
Among the layered dielectric substrates 201 to 205, the through hole 207 serving as a waveguide is formed in the dielectric substrates 201 and 202 disposed adjacent to the printed board 101. In the dielectric substrates 203 to 205, the space area 208 continuous to the through hole 207 is formed. Further, the metal film 206 such as a thin copper film is formed by performing a plating treatment on each of the surfaces of the plurality of layered dielectric substrates 201 to 205. In the metal film 206, the metal film 206a formed between the printed board 101 and the dielectric substrate 201 forms a ground layer (hereinafter also referred to as a ground layer 206a) of the antenna A_1 and the RF circuit 10.
The RF signal S1_1 generated by the RF circuit 10 is supplied to the antenna A_1 through the transmission line W1. The RF signal S1_1 propagates through the through hole 207 serving as a waveguide and reaches the space area 208 of the antenna A_1, and then is emitted into the air.
The antennas A_2 to A_n (not shown) have the same cross-sectional structure as that of the antenna A_1, and thus the descriptions of the antennas A_2 to A_n will be omitted.
As shown in
Further, the metal film 206 is formed on each of the surfaces of the dielectric substrates 201 to 205. To be more specific, the metal film 206 is formed on each of the surfaces of the dielectric substrates 201 to 205 by performing a plating treatment on each of the surfaces of the dielectric substrates 201 to 205 before the dielectric substrates 201 to 205 are layered.
Here, the transmission line W1 for transmitting the RF signal S1_1 is wired to the RF circuit formation layer 301. On the other hand, the transmission line W2 for transmitting signals other than the RF signal S1_1 such as an LO signal, an IF signal, and a power supply voltage is not only wired to the RF circuit formation layer 301 but also wired using the metal film 206 (hereinafter referred to as the metal film 206b) formed between the dielectric substrates 201 and 202. Note that the transmission line W2 wired between the dielectric substrates 201 and 202 are formed by performing a plating treatment while the dielectric substrate is masked with the mask pattern of the transmission line W2 when the metal film 206a is formed between the dielectric substrates 201 and 202. For example, signals other than the RF signal S1_1 such as an LO signal, an IF signal, and a power supply voltage are transmitted from the transmission line W2 formed in the RF circuit formation layer 301 to the transmission line W2 formed by the metal film 206b between the dielectric substrates 201 and 202 through the via V2.
Thus, in the radio communication apparatus 1, the transmission lines W1 and W2 can be wired without increasing the number of layers of the RF circuit formation layer 301. As a result, the transmission line W1 can be wired from the RF circuit 10 right under the through hole 207 of the antenna A_1 without using the via V1, and therefore the RF signal S1_1 is maintained in a high quality state.
In the radio communication apparatus 1, since it is not necessary to use a special wiring structure for wiring in an intersecting manner, the level of difficulty in designing is reduced, and the manufacturing cost is reduced.
As described above, in the radio communication apparatus 1 according to this example embodiment, the transmission line W2 other than the transmission line W1 for transmitting RF signals is formed between the plurality of dielectric substrates, which are components of the antenna, using the metal film provided between the plurality of dielectric substrates. By doing so, in the radio communication apparatus 1 according to this example embodiment, it is not necessary to increase the number of layers of the RF circuit formation layer, so that the transmission line W1 for transmitting the RF signal can be wired without using a via. As a result, the radio communication apparatus 1 according to this example embodiment can transmit (or receive) high-quality RF signals.
In this example embodiment, an example in which a part of the transmission line W2 is formed using the metal film 206b between the dielectric substrates 201 and 202 has been described, but the present disclosure is not limited to this case. A part of the transmission line W2 can be formed by using any metal film 206b between the dielectric substrates 201 to 205.
In this example embodiment, a case where the metal film 206 is formed on each surface of the dielectric substrate 201 to 205 before the dielectric substrate 201 to 205 are layered has been described as an example, but the present disclosure is not limited to this case. The metal film 206 may be formed only on an exposed surface of the dielectric substrates 201 to 205 after the dielectric substrates 201 to 205 are layered. In this case, the metal film 206b is formed by performing a plating treatment only between the dielectric substrates for wiring the transmission line W2 among the plurality of dielectric substrates while the dielectric substrate is masked by the mask pattern of the transmission line W2.
In this example embodiment, a case where the plurality of antennas A_1 to A_n are provided on the printed board 101 has been described as an example, but the present disclosure is not limited to this case. The case where one antenna A_1 is provided on the printed board 101 is included in the scope of the present disclosure as a matter of course.
In this example embodiment, the case where the RF signals S1_1 to S1_n are transmitted from the plurality of antennas A_1 to A_n has been described as an example, but the present disclosure is not limited to this case. The case where the RF signals S1_1 to S1_n are received by the plurality of antennas A_1 to A_n, respectively, is also included in the scope of the present disclosure as a matter of course.
Although the present disclosure has been described with reference to the example embodiments, the present disclosure is not limited by the above. The configuration and details of the present disclosure may be modified in various ways as will be understood by those skilled in the art within the scope of the disclosure.
This application is based upon and claims the benefit of priority from Japanese patent application No. 2018-064147, filed on Mar. 29, 2018, the disclosure of which is incorporated herein in its entirety by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-064147 | Mar 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/004310 | 2/6/2019 | WO | 00 |
