Patent Application
20230378653
The present disclosure relates to an antenna, an information processing apparatus, and a composite antenna apparatus which are capable of being installed in a moving body such as a vehicle, a robot, or a drone.
In recent years, development of autonomous driving of a vehicle such as an ADAS (advanced driver-assistance system) has rapidly been progressing. In such autonomous driving, it is desired to acquire current position information of a vehicle as quickly and accurately as possible by using a reception signal received by an antenna, which is attached to the vehicle, for a satellite positioning system. An easy measure for enhancing acquisition accuracy of the position information is a measure in which signals at multiple frequencies from plural artificial satellites are received by antennas corresponding to the respective frequencies and the position information is thereby calculated based on the respective reception signals. However, in a case of an antenna apparatus for a vehicle, in addition to the respective antennas for receiving the signals at the multiple frequencies, an antenna portion is also implemented which is capable of being adapted to other different frequency bands such as AM and FM bands. Thus, when the respective antennas for receiving the signals at the multiple frequencies are mounted in the same housing, a device itself becomes large and thereby becomes unsuitable for a vehicle.
As for such problems, in Patent Literature 1, the applicant of the present application has suggested an antenna with slots in which two pairs of slots are formed in and two feeding points are mounted on a patch electrode formed with a square conductor. The two pairs of slots have the same shape and size and are arranged in point symmetry with respect to a center point of the square conductor. The two feeding points are mounted in positions which are eccentric slightly outward from the center of the square conductor, power is fed to the two feeding points, and reception of a circularly polarized wave is efficiently performed.
The antenna with slots which is disclosed in Patent Literature 1 is capable of an antenna action conforming to an outer peripheral dimension of the square conductor and also of a slot antenna action conforming to dimensions of the slots and, as one antenna, can receive signals at multiple frequencies which are transmitted from plural artificial satellites. Further, meandering shapes are formed in the slots, flexibility of setting of reception bands of the antenna action and the slot antenna action is thereby improved, and adaptation to a requested reception band becomes easy. Furthermore, in addition to achievement of efficient reception of a circularly polarized wave by two-point feeding, an axial ratio can be made good in a wide frequency band.
Patent Literature 1: International Publication No. WO 2018/164018
In general, a moving body such as a vehicle always three-dimensionally changes its posture in movement. Further, for example, in order to meet a request for an improvement in accuracy of position information in autonomous driving of a vehicle such as an ADAS, it is desirable that an antenna for a satellite positioning system have a high axial ratio for a signal from an artificial satellite in a wide frequency band and have a good axial ratio for a wide elevation angle. In addition, an improvement in accuracy of the position information is desired also for a drone or the like as another moving body than a vehicle. In other words, for example, as for unmanned controlled moving bodies such as vehicles by autonomous driving and small unmanned aircrafts of drones, an improvement in position accuracy is desired more than ever before.
One object of the present disclosure is to contribute to a further improvement in accuracy of a position of a moving body which is derived based on a reception signal by an antenna, for example.
One aspect of the present disclosure provides an antenna including: a dielectric; and a patch electrode and a circuit substrate which are mounted on the dielectric, in which the patch electrode has four feeding terminals, and on the circuit substrate, substrate-side feeding terminals which are electrically connected respectively with the four feeding terminals in a one-to-one manner, a phase circuit which performs a phase shift for signals output from the substrate-side feeding terminals, a combining circuit which combines signals for which the phase shift is performed by the phase circuit, and an amplifier circuit which amplifies signals combined by the combining circuit are mounted.
Another aspect of the present disclosure provides an information processing apparatus being installed in a moving body, the information processing apparatus including: an antenna that includes a patch electrode which has at least four feeding terminals and a circuit substrate which has substrate-side feeding terminals which are electrically connected respectively with the four feeding terminals in a one-to-one manner, a phase circuit which performs a phase shift for signals output from the substrate-side feeding terminals, a combining circuit which combines signals for which the phase shift is performed by the phase circuit, and an amplifier circuit which amplifies signals combined by the combining circuit; and a position information processing circuit which calculates position information of the moving body based on a signal output from the antenna.
Another aspect of the present disclosure provides a composite antenna apparatus including: a first antenna for a satellite positioning system, the first antenna having a patch electrode which has four feeding terminals and a circuit substrate which performs signal processing for a reception signal from the patch electrode; a second antenna which receives a signal in a frequency band different from the first antenna; an antenna base on which the first antenna and the second antenna are situated; and an antenna casing which accommodates, together with the antenna base, the first antenna and the second antenna.
In the present disclosure, compared to one-point feeding or two-point feeding, an axial ratio is improved for wide elevation angles and wide frequencies, and contribution can thereby be made to realization of a further improvement in position accuracy of a moving body. Further, because an antenna is adapted to multiple frequencies, it is not necessary to provide plural antennas adapted to the respective frequencies, thus the present disclosure can contribute to space saving.
Hereinafter, as an example, as to a case where the present disclosure is applied to an antenna for a satellite positioning system (hereinafter, simply referred to as antenna), an embodiment thereof will be described with reference to drawings. In this case, the antenna is capable of simultaneously receiving two frequency bands of an L1 band (1,560 to 1,605 MHz) of a GNSS (global navigation satellite system) and an L5 band (1,150 to 1,210 MHz) of the GNSS, or two frequency bands of the L1 band of the GNSS and an L2 band (1,197 to 1,260 MHz) of the GNSS. In the present embodiment, for convenience of description, orthogonal three-dimensional axes of an X axis, a Y axis, and a Z axis are illustrated in the drawings. The X axis represents a longitudinal direction of the antenna, the Y axis represents a width direction of the antenna, and the Z axis represents a zenith (perpendicularly upper) direction. Further, a +Z axis direction may be referred to as “up”, “upper side”, “zenith”, or “zenith direction”, viewing the antenna from the upper side may be expressed as “top view”, and viewing the antenna from the Y axis may be expressed as “side view”.
A component structure example of the antenna of the present embodiment is illustrated in
The antenna casing 10 is an electric wave transmitting housing which is configured with a top cover 10a and a base cover 10b. The top cover 10a has slightly rounded side portions and a square-shaped opening and is a rigid resin box, for example, a plastic box, in a tubular shape which has a bottom and whose upper bottom portion has a general square shape, and four corner portions of the opening are equivalently notched. Further, in an inner end portion of each of the corner portions, a screw hole corresponding to each screw 101 is threaded. The base cover 10b is a generally square annular body, and in four corner portions, projection portions 111 are formed which are used for positioning with the top cover 10a and through which the screws 101 are caused to pass.
The projection portion 111 is shaped to have such shape and size that the projection portion 111 seals each of the four corner portions of the top cover 10a when the base cover 10b is covered by the top cover 10a. Ribs 112 for supporting a GNSS substrate assembly 12 are formed on the inside of four sides among the corner portions of the base cover 10b, and a cable guide 113 which has a recess is formed in one of those sides. The recess of the cable guide 113 is shaped to have a diameter which is equivalent to or less than an outer diameter of a feeding cable 124 described later. In other words, the recess is shaped to retain the feeding cable 124 pushed thereinto.
The GNSS substrate assembly 12 is configured with a circuit substrate 121 formed with a thin insulation plate which has front and back surfaces, a dielectric 122 which is placed in an almost central portion of the front surface of the circuit substrate 121, a patch electrode 123 which is attached to a front surface of the dielectric 122, a feeding cable 124, and the packing 11 which is configured with a soft insulator such as rubber or silicon.
On the back surface of the circuit substrate 121, a feeding unit including four substrate-side feeding terminals is formed. The feeding unit will later be described in detail. One end of the feeding cable 124 is made electrically connected with an output unit of the feeding unit, and another end is supported by the cable guide 113 of the base cover 10b and is exposed to an outer portion of the antenna casing 10. Further, airtightness and watertightness of one end of the feeding cable 124 are retained by the packing 11. The GNSS substrate assembly 12 is not limited to the above shape. Four corner portions of an attachment tape 13 for causing the screws 101 to pass through the holes of the projection portions 111 of the base cover 10b are notched inward in arc shapes, and the attachment tape 13 is pasted onto a back surface of the base cover 10b.
The patch electrode 123 is a square-shaped metal plate which is generally parallel with a ground conductor (for example, a vehicle roof) and is fixed to a portion on a slightly inner side of an outer periphery of a front surface of the dielectric 122. A structure example of the patch electrode 123 is illustrated in
The distance between the center point of the patch electrode 123 and the position of each of the electrode-side feeding terminals p11, p12, p13, and p14 is set to a distance at which impedance matching (for example, 50 ohms) of the patch electrode 123 is achieved in a used frequency band.
On an inner side of an outer periphery of the patch electrode 123, four slots SL1, SL2, SL3, and SL4 are formed along sides of a square and on the outside with respect to the electrode-side feeding terminals p11, p12, p13, and p14. The “slot” denotes a portion in which the metal plate is notched. The slots SL1, SL2, SL3, and SL4 are positioned in line symmetry with respect to a symmetry axis which passes through the center point of the patch electrode 123 and in point symmetry with respect to the center point.
Further, in the four slots SL1, SL2, SL3, and SL4, meandering (winding) portions SL1m, SL2m, SL3m, and SL4m are formed in generally intermediate positions of straight line portions which are parallel with respective sides. The electrode-side feeding terminals p11, p12, p13, and p14 are formed in almost central portions of the closest meandering (winding) portions SL1m, SL2m, SL3m, and SL4m.
The meandering portions SL1m, SL2m, SL3m, and SL4m are formed to make electrical lengths longer and to make transmission and/or reception frequencies lower than a case where those are absent. Thus, sizes of the meandering portions SL1m, SL2m, SL3m, and SL4m are appropriately adjusted after manufacturing or before manufacturing, fine adjustment of frequencies at which transmission and/or reception are possible thereby becomes possible, design flexibility is increased, and flexible adaptation to requested transmission and/or reception bands becomes possible.
One feature of the antenna 1 of the present embodiment is the point that the patch electrode 123 is present in which the four slots SL1, SL2, SL3, and SL4 conforming to resonance conditions of desired frequencies, the four electrode-side feeding terminals p11, p12, p13, and p14 are one by one present at equivalent distances from the center point of the patch electrode 123, and feeding phases (phases in feeding, the same applies to the following) at the electrode-side feeding terminals p11, p12, p13, and p14 are different by 90 degrees from the feeding phases of the other neighboring electrode-side feeding terminals p11, p12, p13, and p14.
Thus, the patch electrode 123 performs an antenna action for transmitting and/or receiving electric waves at frequencies which satisfy resonance conditions based on the length of one side of the square and on permittivity of the dielectric 122, and a slot action for transmitting and/or receiving electric waves at frequencies which satisfy resonance conditions even in consideration of electrical lengths of the slots SL1, SL2, SL3, and SL4 and the meandering portions SL1m, SL2m, SL3m, and SL4m. In other words, the patch electrode 123 performs a “double resonance” action.
In the antenna action, the frequency which satisfies the resonance conditions is a frequency at which an electrical length defined by the length of one side of the patch electrode 123 and by the permittivity of the dielectric 122 becomes approximately ½ wavelength (and its integer multiples). In the slot action, the frequency which satisfies the resonance conditions is a frequency at which an electrical length defined by the whole length of each of the meandering portions SL1m, SL2m, SL3m, and SL4m and slots SL1, SL2, SL3, and SL4 and by the permittivity of the dielectric 122 becomes approximately ½ wavelength (and its integer multiples).
The whole length of each of the meandering portions SL1m, SL2m, SL3m, and SL4m and slots SL1, SL2, SL3, and SL4 is a length from one end to the other end of an edge of the slot or a length from one end to the other end of an edge of the meandering portion, for example.
Because four-point feeding is performed at the positions in line symmetry and point symmetry while phase shifts of 90 degrees are sequentially performed between the neighboring electrode-side feeding terminals at equivalent amplitudes, an electric wave to be received by the patch electrode becomes a circularly polarized wave. In a case where the phase shifts are performed in right-handed rotation, the electric wave becomes a right-handed circularly polarized wave. In a case of left-handed rotation, the electric wave becomes a left-handed circularly polarized wave.
In other words, in the present embodiment, it becomes easy to realize reception of circularly polarized waves at two frequency bands (for example, the L1 band and the L5 band or the L1 band and the L2 band) of the GNSS by one antenna 1.
In the present embodiment, a description is made about a case where the slots in which the meandering portions are formed are mounted along the respective sides of the square of the patch electrode; however, as long as the slots are positioned in line symmetry with respect to the symmetry axis passing through the center point of the patch electrode 123 and in point symmetry with respect to the center point, the slots may have any shape (for example, shapes in which no meandering portion is provided) and may be positioned in any part (for example, parts along respective corner portions of the square of the patch electrode).
Next, a feeding unit 20 mounted on the circuit substrate 121 will be described.
The whole feeding circuit 20a may be configured with distributed constant lines.
A conductor pattern of the feeding unit 20 is illustrated in
In the feeding unit 20, four substrate-side feeding terminals p21, p22, p23, and p24 are formed in the same positions, in the feeding circuit 20 in a top view, as the positions of the four electrode-side feeding terminals p11, p12, p13, and p14 which are formed on the patch electrode 123. The electrode-side feeding terminal p11 and the substrate-side feeding terminal p21, the electrode-side feeding terminal p12 and the substrate-side feeding terminal p22, the electrode-side feeding terminal p13 and the substrate-side feeding terminal p23, and the electrode-side feeding terminal p14 and the substrate-side feeding terminal p24, which are respectively closest to one another, are directly made electrically connected together by conductive pins or the like.
Matching circuits 211, 212, 213, and 214 are made electrically connected with the four substrate-side feeding terminals p21, p22, p23, and p24 in a one-to-one manner with respect to their corresponding lines. The matching circuits 211, 212, 213, and 214 are circuits which perform impedance matching between the patch electrode 123 and the feeding unit 20, and all of the four circuits are configured with lumped constant circuits in a conductor pattern having the same shape and area and in the same arrangement relationship. A phase shifter 221 which performs a phase shift of +45 degrees is connected with the matching circuit 211, a phase shifter 222 which performs a phase shift of −45 degrees is connected with the matching circuit 212, a phase shifter 223 which performs a phase shift of +45 degrees is connected with the matching circuit 213, and a phase shifter 224 which performs a phase shift of −45 degrees is connected with the matching circuit 214. In the present embodiment, a description will be made about a configuration which uses the matching circuits 211, 212, 213, and 214, however, the present disclosure is capable of being carried out without those matching circuits.
The matching circuits 211, 212, 213, and 214 perform impedance matching for respective reception signals (power), which are four equal parts resulting from division by the patch electrode 123, and output the respective reception signals to the phase shifters 221, 222, 223, and 224 in rear stages. The phase shifter 221 performs a phase shift of +45 degrees for the reception signal (power) output from the matching circuit 211 and outputs the reception signal to a combiner 231 in a rear stage. Similarly, the phase shifter 222 performs a phase shift of −45 degrees for the reception signal (power) output from the matching circuit 212 and outputs the reception signal to the combiner 231 in the rear stage. The phase shifter 223 performs a phase shift of +45 degrees for the reception signal (power) output from the matching circuit 213 and outputs the reception signal to a combiner 232 in a rear stage. The phase shifter 224 performs a phase shift of −45 degrees for the reception signal (power) output from the matching circuit 214 and outputs the reception signal to the combiner 232 in the rear stage.
As illustrated in
The combiner 231 accepts inputs of two reception signals (power) output from the phase shifter 221 and the phase shifter 222 and combines those into one signal. Further, the combiner 232 accepts inputs of two reception signals (power) output from the phase shifter 223 and the phase shifter 224 and combines those into one signal. As a circuit, as illustrated in
An output of the combiner 231 is input to a phase shifter 241. Further, an output of the combiner 232 is input to a phase shifter 242. The phase shifter 241 performs a phase shift of +90 degrees for an input reception signal (power) and outputs the reception signal to a combiner 251 in a rear stage. The phase shifter 242 performs a phase shift of −90 degrees for an input reception signal (power) and outputs the reception signal to the combiner 251 in the rear stage. The combiner 251 accepts inputs of the reception signals (power) output from the phase shifter 241 and the phase shifter 242, combines those reception signals (power), and outputs a combined reception signal to an LNA 261. The LNA 261 amplifies the combined reception signal (power) at a predetermined amplification factor and outputs the combined reception signal to the receiver 271 in a rear stage. The combiners 231, 232, and 251 are Wilkinson dividers, for example. The phase shifters 241 and 242 in the present embodiment correspond to second phase circuits, and the combiner 251 corresponds to a second combining circuit.
Next, the receiver 271 will be described. The receiver 271 has a position information processing circuit which extracts a digital signal from a reception signal (power) output from the feeding unit 20 and in real time calculates a present position of a moving body based on the extracted digital signal. A position calculation algorithm is incorporated in the position information processing circuit, and the position information processing circuit outputs time information and present position information. The receiver 271 may be mounted on the circuit substrate 121 but may be mounted on another circuit substrate on the outside of the antenna casing 10. An information processing apparatus which calculates position information of a moving body such as a vehicle to which the antenna 1 is attached is configured with the antenna 1 and the receiver 271 having the position information processing circuit.
In the following, a description will be made about antenna characteristics of the antenna 1 of the present embodiment which is configured as described above. A simulator was used for an analysis of the antenna characteristics, and a simulation was performed by using a ground conductor with a diameter of 15 cm. Here, in order to compare characteristics in accordance with features, a description will be made about antennas that respectively have a reference example electrode 323 without two-feed slots which is illustrated in
The reference example electrodes 323, 423, and 523 have the same materials, shapes, and outer periphery sizes as the patch electrode of the present embodiment which is illustrated in
The feeding circuit 30 illustrated in
In the two-feed double resonance type, the axial ratio does not become 1 dB or lower at any elevation angle, and in particular, at 1.21 GHz, the axial ratio exceeds 4 dB even at an elevation angle of 0 degree. Further, at 1.61 GHz, the axial ratio becomes approximately 2 dB at an elevation angle of 0 degree, and the axial ratio becomes higher as the elevation angle increases. Thus, in the two-feed double resonance type, in the L2 band of the GNSS and the L1 band of the GNSS, it becomes difficult to acquire accurate position information from the reception signal. On the other hand, in the four-feed double resonance type, in a case where the elevation angle is 0 degree, the axial ratio is near 0 dB at any frequency. In particular, at 1.16 GHz, the axial ratio is about 0.6 even when the elevation angle exceeds 45 degrees. It can be understood that the axial ratio is significantly improved.
It can be understood that in the two-feed type, the directivity characteristics are uneven depending on the frequencies but in the four-feed type, the directivity is directed in the zenith direction regardless of the frequencies.
The above description indicates the characteristics in a case where the LNA 261 is not arranged in a rear stage of the feeding circuit 20a, but even in a case where the LNA 261 is arranged in the rear stage of the feeding circuit 20a, only the gain is changed by the LNA 261, and the characteristics themselves are not changed. In accordance with an arrangement position of the LNA 261, top loss of the antenna 1, that is, passing loss of power from the patch electrode 123 to an initial stage amplifier (the LNA 261 in this example) may be changed.
Referring to those diagrams, in the present example of
Further, in the modification example 2 of
In other words, when it is assumed that the noise factors of the present example are set as 1 at the measurement points of m13 and m14 and set as 1.2 at the measurement points of m15 and m16, in the modification example 1, the noise factors are improved to 0.8 at measurement points of m13 and m24 and to 0.7 at the measurement points of m15 and m16. Further, in the modification example 2, the noise factors are improved to 0.9 at the measurement point of m13 and to 0.8 at measurement points of m14, m25, and m26. In other words, it has been found that the LNAs 261 are arranged in positions as close as possible to the patch electrode 123, in other words, in the front stages of the phase shifters 221 to 224, 241, and 242 and the combiners 231, 232, and 251 and a total noise factor of the antenna 1 can thereby be made better.
The feeding circuit 20a may be practiced in various forms other than
The antenna 1 of the present embodiment is capable of being installed alone in a moving body such as a robot or a drone and is also usable for an antenna apparatus for a vehicle in which antenna portions for various frequency bands are installed in one casing, in recent years.
Because the antenna 1 has directivity in the zenith direction and the axial ratio in the zenith direction is considerably improved compared to antennas in related art, even when the planar antennas 102, 103, and 104 for other frequency bands are arranged close to the antenna 1, the antenna 1 can accurately receive a signal for position information calculation at least in the GNSS frequency band.
A description will be made about a demonstration experiment for comparing position accuracy by using the four-feed double resonance antenna 1 (in which the receiver 271 is installed) in a configuration illustrated in
The demonstration experiment was performed in the following manner. First, a display device for displaying position information output by the receiver 271 of each of the antennas (the antenna 1 and the reference example antenna) was connected to the receiver 271 and was installed in a vehicle. The position information of the vehicle traveling on a road in a poor environment for receiving electric waves was calculated, and the calculated position information of the vehicle was displayed, together with a map, on the display device. Then, the accuracy of the position information of the vehicle with respect to the map was visually checked for the four-feed double resonance antenna 1 and the two-feed double resonance reference example antenna. The road on which the vehicle traveled is an ordinary road which is present directly below an elevated toll road, in other words, an ordinary road on which an elevated toll road is present in the zenith direction of each of the antennas.
As described above, it has been demonstrated that the antenna 1 of the present embodiment can calculate the position information with higher accuracy than a first reference example antenna with two-feed double resonance even when the vehicle travels on the road, on which an obstacle is present in the zenith direction, in either one of the first zone and the second zone.
From the above description of the present embodiment, for example, the following configurations and working effects by those are derived.
(1) An antenna including: a dielectric; and a patch electrode and a circuit substrate which are mounted on the dielectric, in which the patch electrode has four feeding terminals, and on the circuit substrate, substrate-side feeding terminals which are electrically connected respectively with the four feeding terminals in a one-to-one manner, a phase circuit which performs a phase shift for signals output from the substrate-side feeding terminals, a combining circuit which combines signals for which the phase shift is performed by the phase circuit, and an amplifier circuit which amplifies signals combined by the combiner are mounted.
In the antenna in this configuration, the antenna characteristics in the zenith direction are considerably improved compared to an antenna which has the patch electrode illustrated in
(2) The antenna, in which the circuit substrate is mounted on a surface side opposite to a surface side on which the patch electrode of the dielectric is mounted and each of the four feeding terminals is opposed to a corresponding electrically connected section in the substrate-side feeding terminal.
In the antenna in this configuration, because each of the four feeding terminals is made electrically connected with the corresponding electrically connected section in the substrate-side feeding terminal in a shortest distance defined by a thickness of the dielectric, the antenna is less likely to be subject to external influences.
(3) The antenna, in which four slots are formed in the patch electrode.
The antenna in this configuration performs an antenna action for transmitting and/or receiving electric waves at frequencies which satisfy resonance conditions based on the size of the patch electrode and on permittivity of the dielectric and a slot action for transmitting and/or receiving electric waves at frequencies which satisfy resonance conditions even in consideration of electrical lengths of the slots. In other words, a “double resonance” action becomes possible.
(4) The antenna, in which feeding phases of the four feeding terminals are respectively different by 90 degrees from feeding phases of the other neighboring feeding terminals.
By the antenna in this configuration, an improvement in the axial ratio of a circularly polarized wave becomes possible.
(5) The antenna, in which the phase circuit includes a first phase circuit and a second phase circuit, the combining circuit includes a first combining circuit and a second combining circuit, the first phase circuit is arranged in a rear stage of the substrate-side feeding terminal, the second phase circuit is arranged in a rear stage of the first phase circuit, the first combining circuit is arranged in a rear stage of the first phase circuit and in a front stage of the second phase circuit, the second combining circuit is arranged in a rear stage of the second phase circuit, and the amplifier circuit is arranged in a rear stage of the second combining circuit.
The first phase circuit has two phase shifters which perform a phase shift of 45 degrees in a positive direction for input signals and two phase shifters which perform a phase shift of 45 degrees in a negative direction for input signals, for example.
Further, the second phase circuit has a phase shifter which performs a phase shift of 90 degrees in the positive direction for an input signal and a phase shifter which performs a phase shift of 90 degrees in the negative direction for an input signal, for example.
In the antenna in this configuration, because phase shifts of predetermined amounts are respectively performed for plural signals which are received in plural positions and are dividedly input and the plural signals are thereafter combined, circularly polarized waves propagated from plural directions can highly accurately be received.
In one embodiment, the combining circuit is a Wilkinson divider. In such a configuration, a main portion of a circuit can be realized with a conductor pattern group which is printed on the substrate, and mass production of the antenna thereby becomes easy.
(6) The antenna, in which the amplifier circuit is mounted in a front stage of the combining circuit.
Further, in the antenna, for example, the phase circuit includes a first phase circuit and a second phase circuit, the combining circuit includes a first combining circuit and a second combining circuit, the first phase circuit is arranged in a rear stage of the substrate-side feeding terminal, the second phase circuit is arranged in a rear stage of the first phase circuit, the first combining circuit is arranged in a rear stage of the first phase circuit and in a front stage of the second phase circuit, the second combining circuit is arranged in a rear stage of the second phase circuit, and the amplifier circuit is arranged in a front stage of the first combining circuit or the second combining circuit.
In the antenna in this configuration, the reception signal is amplified in the front stage of the combining circuit, passing loss can thereby be reduced, and a signal which is excellent in a signal-to-noise ratio can be output.
(7) An information processing apparatus being installed in a moving body, the information processing apparatus including: any one of the above antennas; and a position information processing circuit which calculates position information of the antenna based on a signal output from the antenna. The information processing apparatus in this configuration can highly accurately calculate position information of an autonomously driven vehicle, for example.
(8) In a composite antenna apparatus including: a first antenna for a satellite positioning system, the first antenna having a patch electrode which has four feeding terminals and a circuit substrate which performs signal processing for a reception signal from the patch electrode; a second antenna which receives a signal in a frequency band different from the first antenna; an antenna base on which the first antenna and the second antenna are situated; and an antenna casing which accommodates, together with the antenna base, the first antenna and the second antenna, the first antenna adapted to multiple frequencies are accommodated, together with the other antenna (second antenna), in the same accommodation space, and size reduction of the device and space saving thereby become possible.
(9) In an antenna including: a dielectric; a patch electrode which is mounted on the dielectric; and four feeding terminals which are mounted on the patch electrode, in which feeding phases of the four feeding terminals are respectively different by 90 degrees from feeding phases of the other neighboring feeding terminals and each of the four feeding terminals is directly electrically connected with a substrate-side feeding terminal that is mounted on a side of a circuit substrate which performs signal processing for a reception signal from the patch electrode, an improvement in the axial ratio of a circularly polarized wave becomes possible.
(10) A configuration may be possible in which each of the four slots in the patch electrode is a slot which has a meandering portion and has the same shape. In such a configuration, because a frequency which satisfies the resonance conditions can be adjusted by the slot, flexibility of antenna design can be increased.
Further, as illustrated in
(11) An antenna including: a dielectric; and a patch electrode and a circuit substrate which are mounted on the dielectric, in which in the patch electrode, four feeding terminals are formed in point symmetry with respect to a center point of the patch electrode, and on the circuit substrate, four substrate-side feeding terminals which are electrically connected respectively with the four feeding terminals in a one-to-one manner, four first phase circuits each of which performs a phase shift of the same amount in a shift direction opposite to neighboring signals for a signal output from the closest substrate-side feeding terminal among the four substrate-side feeding terminals, two combining circuits each of which combines signals output from the two neighboring first phase circuits among the four first phase circuits, two second phase circuits each of which performs a phase shift of the same amount in a shift direction opposite to a neighboring signal for a signal output from one first combining circuit of the two first combining circuits, and a second combining circuit which combines output signals of the two second phase circuits are mounted.
In the antenna in such a configuration, for four signals which are received by the patch electrode of four-point feeding and are input to the circuit substrate through the substrate-side feeding terminals, the corresponding first phase circuits perform phase shifts of the same amount in shift directions opposite to the respective neighboring signals, and thereafter, each of the first combining circuits combines two signals. Then, for each of two signals resulting from combining, the second phase circuit performs a phase shift of the same amount in a shift direction opposite to the neighboring signal, and thereafter, the two signals are combined into one signal by the second combining circuit.
In a case where the positions of the four feeding terminals in the patch electrode are positions resulting from division of 360 degrees into four equal parts with the center point being an origin, a phase difference of 90 degrees (90 degrees, 180 degrees, 270 degrees, and 360 degrees (0 degree)) occurs between the two neighboring feeding terminals, and the phase differences themselves are exhibited as phase differences of four signals output from the feeding terminals. On the side of the circuit substrate which is electrically connected with each feeding terminal of the patch electrode, it is necessary to combine the four signals into one signal by compensating the phase differences among the four signals.
One of measures for compensating phase differences among signals is to combine the signals by performing phase shifts for the other signals such that the phases are matched with the phase of any one of the signals. However, when a phase shift is performed for a signal, as the phase amount of a shift becomes larger, passing loss of the signal (passing loss of power) becomes larger.
For example, in a case where the phase shift amount of one of two signals as targets is set to 0 degrees, the phase shift amount of the other signal is set to 90 degrees, and those signals are combined, passing loss does not occur to the signal with the phase shift amount of 0, and attenuation of an amplitude is thus small. However, as for the signal with the phase shift amount of 90 degrees, attenuation of the amplitude becomes huge due to an influence of passing loss. Thus, an amplitude difference between the two signals becomes extremely large, and undesirable influences might occur to antenna characteristics in a case where those are combined, particularly, gain and axial ratio.
In the antenna in the above configuration, the phase shift of the same amount (45 degrees or 90 degrees in the above example) in the shift direction opposite to the neighboring signal (+45 degrees, −45 degrees and +90 degrees, −90 degrees in
Accordingly, the amplitude of each of the signals resulting from the phase shift becomes almost equivalent regardless of a reception frequency, and undesirable influences on the gain and axial ratio can be reduced. In other words, it becomes possible to widen a band, to reduce unevenness of directivity directed in the zenith direction, and to enlarge an elevation angle range in which the axial ratio is good.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-163014 | Sep 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/034200 | 9/16/2021 | WO |
