Communication device

Abstract

A communication device according to the present application houses a first antenna, a second antenna, and a waveguide structure in the same housing. The second antenna has a higher operating frequency than the first antenna. The second antenna is an array antenna including a plurality of radiating elements. The waveguide structure includes a unit waveguide that is disposed outside a range of a half-value angle of a main beam as viewed from the first antenna and in a path of an electric wave received by the second antenna, and attenuates an electric wave of the operating frequency of the first antenna more greatly than an electric wave of the operating frequency of the second antenna.

Description

Technical Field

[0001] The present invention relates to a communication device that operates at at least two frequencies. Background Technology

[0002] Patent Document 1 discloses a planar array antenna operating at two frequencies. The antenna comprises a first and a second planar array antenna element arranged in a layered configuration. The first planar array antenna element operates relatively in a low-frequency band, while the second planar array antenna element operates relatively in a high-frequency band. The first planar array antenna element is disposed above the second planar array antenna element. A ground plane is disposed between the first and second planar array antenna elements. The patch of the first planar array antenna element and the ground plane have frequency selectivity that is transparent to the operating frequency band of the second planar array antenna element. Furthermore, the ground plane reflects radio waves at the operating frequency of the first planar array antenna element.

[0003] Patent Document 1: Japanese Patent Publication No. 2000-514614

[0004] In conventional antennas, multiple holes are provided in the patch and ground plane of the first planar array antenna element, which is positioned above the second planar array antenna element, to make it transparent at the operating frequency of the second antenna element. However, it is difficult to make the patch and ground plane of the first planar array antenna element completely electrotransparent. Here, "electrotransparency" means that the effect on radio waves is almost equivalent to that of air. Therefore, the radio waves transmitted and received by the second planar array antenna element are attenuated to some extent due to the patch and ground plane of the first planar array antenna element.

[0005] If two antennas are arranged side-by-side horizontally without overlapping, the radio waves transmitted and received by one antenna are less likely to be affected by the other antenna. However, if radio waves radiated from a low-frequency antenna are received by a high-frequency antenna, higher harmonics are generated during the processing of the received signal. These higher harmonics then become noise for the received signal of the high-frequency radio waves. Summary of the Invention

[0006] The object of the present invention is to provide a communication device that, in a communication device having two antennas operating at different frequencies, reduces the impact of high-order harmonics of the received signal radiated from the low-frequency antenna and received by the high-frequency antenna on the communication of the high-frequency antenna.

[0007] According to one aspect of the present invention, a communication device is provided.

[0008] It has a first antenna, a second antenna, and a waveguide structure housed in the same housing.

[0009] The operating frequency of the second antenna is higher than that of the first antenna.

[0010] The aforementioned second antenna is an array antenna containing multiple radiating elements.

[0011] The aforementioned waveguide structure includes a unit waveguide that attenuates the radio waves at the operating frequency of the first antenna significantly compared to the radio waves at the operating frequency of the second antenna. The unit waveguide is located outside the range of the half-value angle of the main beam when viewed from the first antenna and is positioned in the path of the radio waves received by the second antenna.

[0012] Before the radio waves at the operating frequency of the first antenna are reflected by the radio wave reflector and received by the second antenna, the waveguide structure attenuates the radio waves at the operating frequency of the first antenna. Therefore, even if higher harmonics of the received signal are generated after reception by the second antenna, the signal strength of the higher harmonics is low. Thus, the impact of these higher harmonics on the signal reception processing of the second antenna can be reduced. Attached Figure Description

[0013] Figure 1A This is a top view of the antenna device used in the communication device of the first embodiment. Figure 1B yes Figure 1A A sectional view on the dashed line 1B-1B. Figure 1C This is a perspective view of the waveguide structure included in the communication device of the first embodiment.

[0014] Figure 2 This is a block diagram of the radar function section of the communication device in the first embodiment.

[0015] Figure 3 This is a block diagram of the communication function portion of the communication device in the first embodiment.

[0016] Figure 4 This is a schematic diagram of the communication device of the first embodiment and the radio wave reflector present in the radio wave radiation space of the communication device.

[0017] Figure 5 This is a graph illustrating an example of the change in signal strength from the first antenna and the second antenna, to the reflection of the radio wave reflector, and finally to the detection by the second transmitting and receiving circuit.

[0018] Figure 6A This is a cross-sectional view of the communication device according to the second embodiment. Figure 6B This is a cross-sectional view of a communication device according to a variation of the second embodiment.

[0019] Figure 7A This is a top view of the antenna device used in the communication device of the third embodiment. Figure 7B yes Figure 7AA cross-sectional view of the communication device on the dashed line 7B-7B.

[0020] Figure 8 This is a cross-sectional view of the communication device according to the fourth embodiment.

[0021] Figure 9A This is a top view of the communication device according to the fifth embodiment. Figure 9B yes Figure 9A A sectional view on the dashed-dot line 9B-9B.

[0022] Figure 10A This is a top view of the communication device according to the sixth embodiment. Figure 10B yes Figure 10A A sectional view on the dashed line 10B-10B.

[0023] Figure 11A This is a top view of the communication device according to the seventh embodiment. Figure 11B yes Figure 11A A sectional view on the dashed line 11B-11B. Detailed Implementation

[0024] [First Embodiment]

[0025] Reference Figures 1A to 4 The communication device of the first embodiment will be described below.

[0026] Figure 1A This is a top view of the antenna device used in the communication device of the first embodiment. Figure 1B yes Figure 1A A sectional view on the dashed line 1B-1B. Figure 1C This is a perspective view of the waveguide structure included in the communication device of the first embodiment.

[0027] As the module substrate 30 ( Figure 1B The first antenna 11 and the second antenna 12 are disposed on the support surface 31 of one side of the module substrate 30. The module substrate 30 also functions as a support member supporting the first antenna 11 and the second antenna 12. The first antenna 11 includes a plurality of first radiating elements 11a, and the second antenna 12 includes a plurality of second radiating elements 12a. The module substrate 30 includes a ground plane 32 disposed inside.

[0028] A patch antenna is constructed using a first radiating element 11a, a second radiating element 12a, and a ground plane 32. The first antenna 11 is an array antenna containing multiple first radiating elements 11a, and the second antenna 12 is an array antenna containing multiple second radiating elements 12a. The operating frequency f2 of the second antenna 12 is higher than the operating frequency f1 of the first antenna 11. Here, the operating frequency of the antenna is defined as the frequency with the highest antenna gain.

[0029] When viewed from above, the plurality of first radiating elements 11a are arranged, for example, in a matrix of two rows and two columns, and the second radiating elements 12a are arranged, for example, in a matrix of three rows and four columns.

[0030] A portion of the housing 50 is spaced apart from the support surface 31 of the module substrate 30. A waveguide structure 20 is disposed between the support surface 31 of the module substrate 30 and the housing 50. The waveguide structure 20 contacts both the module substrate 30 and the housing 50. For example, the waveguide structure 20 is located outside the range of the half-value angle of the main beam when viewed from the first antenna 11, and is positioned in the path of the radio waves received by the second antenna 12. Preferably, the waveguide structure 20 is configured not to overlap with the first antenna 11 when viewed from above, and includes the second antenna 12.

[0031] Waveguide structure 20 ( Figure 1C The device includes a metal wall that is configured in a lattice pattern when viewed from above. Corresponding to the plurality of openings 21 in the lattice-shaped metal wall, a plurality of second radiating elements 12a of the second antenna 12 are disposed. Specifically, each second radiating element 12a is disposed inside its corresponding opening 21 when viewed from above. The relative positional relationship between the second radiating element 12a and its corresponding opening 21 is the same for all the second radiating elements 12a.

[0032] Within the lattice-shaped metal wall, the portion forming the sidewall of each of the multiple openings 21 functions as a waveguide (hereinafter referred to as a unit waveguide) to allow radio waves of the desired wavelength to pass through. Additionally, for radio waves with wavelengths sufficiently long relative to the size of the openings 21, the waveguide structure 20 functions as a reflector. Specifically, the waveguide structure 20 allows radio waves at the operating frequency of the second antenna 12 to pass through, while significantly attenuating the radio waves at the operating frequency of the first antenna 11 compared to those at the operating frequency of the second antenna 12.

[0033] Figure 2 This is a block diagram of the radar functional section of the communication device according to the first embodiment. The radar functional section includes Time Division Multiple Access (TDMA), Frequency Modulated Continuous Wave (FMCW), and Multiple-Input Multiple-Output (MIMO) functions. A portion of the plurality of second radiating elements 12a constitutes a transmitting second antenna 12T, and the remaining plurality of second radiating elements 12a constitute a receiving second antenna 12R.

[0034] The second transmitting and receiving circuit 42 supplies high-frequency signals to a plurality of second radiating elements 12a of the transmitting second antenna 12T. The high-frequency signals received by the plurality of second radiating elements 12a of the receiving second antenna 12R are input to the second transmitting and receiving circuit 42. The second transmitting and receiving circuit 42 includes a signal processing circuit 80, a local oscillator 81, a transmitting processing unit 82, and a receiving processing unit 85.

[0035] The local oscillator 81 outputs a local signal SL whose frequency increases or decreases linearly with time, based on the chirp control signal Sc from the signal processing circuit 80. The local signal SL is given to the transmitting processing unit 82 and the receiving processing unit 85.

[0036] The transmission processing unit 82 includes multiple switches 83 and a power amplifier 84. The switches 83 and power amplifier 84 are configured according to the second radiating element 12a constituting the second antenna 12T for transmission. The switches 83 are switched based on a switch control signal Ss from the signal processing circuit 80. When the switch 83 is on, the local signal SL is input to the power amplifier 84. The power amplifier 84 amplifies the power of the local signal SL and supplies it to the corresponding second radiating element 12a.

[0037] The radio waves radiated from the second antenna 12T for transmitting are reflected by the target, and the reflected waves are received by the second antenna 12R for receiving.

[0038] The receiving processing unit 85 includes multiple low-noise amplifiers 87 and a mixer 86. The low-noise amplifiers 87 and the mixer 86 are arranged according to the second radiating elements 12a constituting the second antenna 12R for receiving. The echo signal Se received by the multiple second radiating elements 12a constituting the second antenna 12R for receiving is amplified by the low-noise amplifiers 87. The mixer 86 multiplies the amplified echo signal Se with the local signal SL to generate a beat signal Sb.

[0039] The signal processing circuit 80 includes, for example, an AD converter and a microcomputer, which calculates the distance and orientation to the target by performing signal processing on the beat signal Sb.

[0040] Figure 3 This is a block diagram of the communication function portion of the communication device according to the first embodiment. A high-frequency signal is supplied from the first transmitting and receiving circuit 41 to the first radiating element 11a of the first antenna 11, and the high-frequency signal received by the first radiating element 11a is input to the first transmitting and receiving circuit 41.

[0041] The first transmit / receive circuit 41 includes a baseband integrated circuit element (BBIC) 110 and a high-frequency integrated circuit element (RFIC) 90. The high-frequency integrated circuit element 90 includes an intermediate frequency amplifier 91, a mixer for up / down conversion 92, a transmit / receive switching switch 93, a power divider 94, multiple phase shifters 95, multiple attenuators 96, multiple transmit / receive switching switches 97, multiple power amplifiers 98, multiple low-noise amplifiers 99, and multiple transmit / receive switching switches 100.

[0042] First, the transmission function is explained. An intermediate frequency (IF) signal is input from the baseband integrated circuit element 110 to the up / down converter 92 via an intermediate frequency amplifier 91. The high-frequency signal generated by up-converting the IF signal in the up / down converter 92 is input to the power divider 94 via a transmit / receive switch 93. The high-frequency signals, after being divided in the power divider 94, are input to the first radiating element 11a via a phase shifter 95, an attenuator 96, a transmit / receive switch 97, a power amplifier 98, and a transmit / receive switch 100.

[0043] Next, the receiving function will be described. The high-frequency signals received by each of the multiple first radiating elements 11a are input to the power divider 94 via the transmit / receive switch 100, low-noise amplifier 99, transmit / receive switch 97, attenuator 96, and phase shifter 95. The high-frequency signal synthesized in the power divider 94 is input to the up / down converter mixer 92 via the transmit / receive switch 93. The intermediate frequency (IF) signal generated by down-converting the high-frequency signal in the up / down converter mixer 92 is input to the baseband integrated circuit element 110 via the IF amplifier 91.

[0044] Next, refer to Figure 4 The superior effects of the first embodiment will be explained.

[0045] Figure 4 This is a schematic diagram of a communication device according to the first embodiment and an electromagnetic reflector present in the electromagnetic radiation space of the communication device. An electromagnetic reflector 60 exists in the electromagnetic radiation space of the first antenna 11 and the second antenna 12. The first antenna 11 is used, for example, in a fifth-generation mobile communication system (5G communication system) and operates in the 26 GHz band. The second antenna 12 is used, for example, in a millimeter-wave radar or gesture sensor system and operates at a frequency of 79.5 GHz.

[0046] The waveguide structure 20 allows almost all radio waves at the operating frequency of the second antenna 12, i.e., 79.5 GHz, to pass through, while significantly attenuating radio waves in the operating frequency band of the first antenna 11. Radio waves radiated from the second antenna 12 are reflected by the radio wave reflector 60, and the reflected waves are received by the second antenna 12.

[0047] The radio waves radiated from the first antenna 11 are also reflected by the radio wave reflector 60, and the reflected waves enter the second antenna 12. The antenna gain of the second antenna 12 is maximum at its operating frequency of 79.5 GHz, but it also has some gain in the operating frequency band of the first antenna 11. Therefore, reflected waves of radio waves, for example, in the 26 GHz band, are also received by the second antenna 12. In the second transmitting and receiving circuit 42 ( Figure 2When the low-noise amplifier amplifies a signal in the 26 GHz band, higher harmonics are generated due to the nonlinearity of the low-noise amplifier. The third higher harmonic of the signal in the 26 GHz band contains signals with frequencies consistent with or close to 79.5 GHz. Therefore, the third higher harmonic of the received signal in the 26 GHz band becomes noise for the signal transmitted and received by the second antenna 12.

[0048] In the first embodiment, the waveguide structure 20 attenuates the radio waves radiated from the first antenna 11, reflected by the radio wave reflector 60, and incident on the second antenna 12. Therefore, the intensity of the third higher harmonic generated due to the nonlinearity of the low-noise amplifier 87 is also reduced. Thus, the impact of noise caused by the radio waves radiated from the first antenna 11 on the signals transmitted and received by the second antenna 12 can be reduced.

[0049] Furthermore, in the first embodiment, the relative positional relationship between the plurality of second radiating elements 12a of the second antenna 12 and the opening 21 of their corresponding waveguide structure 20 is the same for all the second radiating elements 12a. Therefore, it is possible to suppress the antenna gain deviation of a single second radiating element 12a.

[0050] Next, refer to Figure 5 The required attenuation amount for waveguide structure 20 is explained.

[0051] Figure 5 This indicates that the radiation is emitted from the first antenna 11 and the second antenna 12, and is reflected by the radio wave reflector 60. Figure 4 ) reflected and received by the second transmitting and receiving circuit 42 ( Figure 2 A graph showing an example of how signal strength changes until detection is performed. The vertical axis represents signal strength in dBm.

[0052] The horizontal axis represents the antenna's equivalent isotropic radiated power (EIRP) and important factors affecting signal strength variation, namely, the transmission loss of the radio wave, the loss caused by the radar cross section (RCS) of the radio wave reflector, and the waveguide structure 20 ( Figure 1A , Figure 1B The transmission loss caused by the antenna, the receiving gain of the antenna, and the efficiency of the generation of the third higher harmonic caused by the nonlinearity of the low-noise amplifier.

[0053] exist Figure 5The diagram illustrates the use of a second antenna 12 for a 79.5 GHz millimeter-wave radar and a first antenna 11 for transmitting and receiving signals in the 26 GHz band of a 5G communication system. The first antenna 11 radiates 26.5 GHz radio waves within the 26 GHz band, while the second antenna 12 radiates 79.5 GHz radio waves. The frequency of the third higher harmonic radiated from the first antenna 11 is equal to the frequency of the fundamental wave radiated from the second antenna 12.

[0054] Figure 5 The thick solid lines in the graph represent variations in the signal strength associated with the 79.5 GHz radio wave radiated from the second antenna 12. Areas with relatively high-density shadows represent the range of signal strength associated with the 79.5 GHz radio wave radiated from the second antenna 12. The thinner solid lines represent variations in the signal strength associated with the 26.5 GHz radio wave radiated from the first antenna 11. Areas with relatively low-density shadows represent the range of signal strength associated with the 26.5 GHz radio wave radiated from the first antenna 11. The dashed lines represent the signal strength associated with the 26.5 GHz radio wave radiated from the first antenna 11 without the waveguide structure 20 configured.

[0055] Assume the EIRP of the fundamental wave from the first antenna 11 is 30 dBm. At this time, the EIRP of, for example, the third higher harmonic is approximately -4 dBm. The EIRP of the 79.5 GHz radio wave radiated from the second antenna 12 used by the radar system needs to be set sufficiently high compared to the EIRP of the third higher harmonic radiated from the first antenna 11. For example, the EIRP of the second antenna 12 at the frequency of 79.5 GHz should be set to 39 dBm, which is sufficiently large relative to -4 dBm.

[0056] First, the radar system including the second antenna 12 will be described. It is assumed that a patch array antenna consisting of eight traveling-wave patterned patch arrays arranged side-by-side is used as the second antenna 12. With an antenna gain of 25 dBi, an EIRP of 39 dBm can be achieved by setting the input power at one port to 5 dBm. When detecting a radio wave reflector 100 m away, the round-trip distance of the radio wave is 200 m. Its transmission loss is approximately 116 dB. Therefore, the signal strength after considering the transmission loss is -77 dBm. Furthermore, if the radar cross-section (RCS) of the radio wave reflector is assumed to be in the range of -10 dB to +10 dB, the signal strength after considering the RCS of the radio wave reflector is between -87 dBm and -67 dBm.

[0057] The waveguide structure 20 allows almost all of the 79.5 GHz radio wave to pass through, thus causing almost no loss. Therefore, the signal strength after passing through the waveguide structure 20 is between -87 dBm and -67 dBm. Assuming the receiving gain of the second antenna 12 is 25 dBi, the signal strength of the received signal from the second antenna 12 is between -62 dBm and -42 dBm. Therefore, the second transmit / receive circuit 42 is preferred. Figure 2 The receiver sensitivity RS should be at least lower than -62dBm. Considering a margin of about 10dB, a receiver sensitivity RS of about -72dBm is preferred.

[0058] Next, the impact of the radio waves radiated from the first antenna 11 used in the 5G communication system on the radar system will be explained. In order to prevent the third higher harmonic of the 26.5 GHz fundamental wave radiated from the first antenna 11 from affecting the radar system, the signal strength of this higher harmonic needs to be smaller than the receiving sensitivity RS of the radar system, i.e., -72 dBm.

[0059] The EIRP of the first antenna 11 at 26.5 GHz is, for example, 30 dBm, as described above. As an example, if the radiation from the first antenna 11 is reflected by a radio wave reflector 1 m in front and enters the second antenna 12, the transmission loss over the 2 m round trip is approximately 67 dB. Therefore, the signal strength after accounting for the transmission loss is -37 dBm. With an obstacle RCS of approximately -10 dB, the signal strength after accounting for the obstacle RCS is -47 dBm.

[0060] First, let's explain the case without the waveguide structure 20. With a receiving gain of 25 dBi at 79.5 GHz for the second antenna 12, the receiving gain at 26.5 GHz is lower. For example, the receiving gain at 26.5 GHz is 0 dBi. In this case, the signal strength of the 26.5 GHz received signal by the second antenna 12 is -47 dBm. If the efficiency of the third higher harmonic generation caused by the nonlinearity of the low-noise amplifier is set to -20 dB, the signal strength of the third higher harmonic at the frequency of 79.5 GHz after passing through the low-noise amplifier is -67 dBm.

[0061] The signal strength is greater than the receiver sensitivity RS, i.e., -72dBm, so it is detected as a valid signal by the radar system. Therefore, the 26.5GHz radio wave received by the second antenna 12 must be attenuated in the waveguide structure 20 before reception.

[0062] In order to make the signal strength of the third higher harmonic lower than the receiver sensitivity RS, such as Figure 5As shown by the thinner solid line, an attenuation of approximately 10 dB is preferred, and an attenuation of approximately 20 dB with a margin is more preferable. By attenuating the 26.5 GHz radio wave by 10 dB in the waveguide structure 20, the signal strength of the third higher harmonic can be made lower than the receiving sensitivity RS of the radar system. Furthermore, by attenuating the 26.5 GHz radio wave by 20 dB in the waveguide structure 20, the signal strength of the third higher harmonic can be made sufficiently low compared to the receiving sensitivity RS of the radar system.

[0063] Although Figure 5 Various assumptions are introduced in the examples shown, but these assumptions reflect the actual usage in radar systems and 5G communication systems. Therefore, generally speaking, it is preferable that the attenuation of the waveguide structure 20 for the radio waves at the operating frequency of the first antenna 11 is 10 dB or more, and more preferably 20 dB or more. The attenuation of the waveguide structure 20 for the radio waves can be adjusted by adjusting the height of the waveguide structure 20 (equivalent to the length of the waveguide).

[0064] [Second Embodiment]

[0065] Next, refer to Figure 6A The communication device of the second embodiment will be described below. Hereinafter, the communication device compared to the first embodiment (…) Figure 1A , Figure 1B , Figure 1C The same composition is omitted.

[0066] Figure 6A This is a cross-sectional view of the communication device according to the second embodiment. In the communication device of the first embodiment, the waveguide structure 20 ( Figure 1B The waveguide structure 20 is in contact with both the module substrate 30 and the housing 50. In contrast, in the second embodiment, the waveguide structure 20 is fixed to the housing 50 with an adhesive and does not contact the module substrate 30. Alternatively, the housing 50 and the waveguide structure 20 can be manufactured by insert molding.

[0067] When the module substrate 30 is installed inside the housing 50, the multiple second radiating elements 12a of the second antenna 12 are aligned with the waveguide structure 20. This allows the positional relationship between the multiple second radiating elements 12a and the waveguide structure 20 when viewed from above to be the same as in the first embodiment.

[0068] Next, refer to Figure 6B The communication device of the modified example of the second embodiment will be described.

[0069] Figure 6B This is a cross-sectional view of a communication device according to a variation of the second embodiment. In this variation, the waveguide structure 20 is fixed to the module substrate 30 using adhesive and does not contact the housing 50.

[0070] Even if, as in the second embodiment or its variations, the waveguide structure 20 is configured not to contact either the module substrate 30 or the housing 50, the same excellent effect as in the first embodiment can be obtained.

[0071] [Third Embodiment]

[0072] Next, refer to Figure 7A as well as Figure 7B The communication device of the third embodiment will be described below. Hereinafter, the communication device compared to the first embodiment (…) Figure 1A , Figure 1B , Figure 1C The same composition is omitted.

[0073] Figure 7A This is a top view of the antenna device used in the communication device of the third embodiment. Figure 7B yes Figure 7A A cross-sectional view along the dashed line 7B-7B. In the first embodiment, the waveguide structure 20 ( Figure 1A , Figure 1C The first one is composed of a lattice-shaped metal wall. In contrast, in the third embodiment, the waveguide structure 20 is composed of multiple conductor pillars 22 and a lattice-shaped conductor pattern 23.

[0074] A dielectric film 33 covering the first antenna 11 and the second antenna 12 is disposed on the support surface 31 of the module substrate 30. Multiple conductor pillars 22, arranged along a grid of straight lines when viewed from above, are embedded in the dielectric film 33. Second radiating elements 12a of the second antenna 12 are disposed in the gaps between the grid of straight lines formed by the conductor pillars 22.

[0075] The upper ends of multiple conductor pillars 22 are exposed on the upper surface of the dielectric film 33. A conductor pattern 23 is configured on the dielectric film 33 to electrically connect the upper ends of the conductor pillars 22 exposed on the upper surface of the dielectric film 33. The lower ends of the multiple conductor pillars 22 reach and are electrically connected to the ground plane 32 within the module substrate 30. The spacing of the multiple conductor pillars 22 is set to a degree that allows the opening of the grid formed by the multiple conductor pillars 22 to function as a waveguide for the radio waves at the operating frequency of the first antenna 11. For example, the spacing of the multiple conductor pillars 22 is set to be less than 1 / 4 of the wavelength of the radio waves at the operating frequency of the second antenna 12 within the dielectric film 33. The multiple conductor pillars 22, configured to surround a second radiating element 12a when viewed from above, and the conductor pattern 23, which electrically connects the upper ends of these conductor pillars to each other, function as a unit waveguide corresponding to the second radiating element 12a.

[0076] Next, the superior effects of the third embodiment will be explained.

[0077] In the third embodiment, the waveguide structure 20 also attenuates the radio waves in the operating frequency band of the first antenna 11, thus achieving the same excellent effect as in the first embodiment. The higher the waveguide structure 20 is from the support surface 31 to its upper end, the greater the attenuation of the radio waves. In the third embodiment, the opening 21 of the waveguide structure 20 is filled with a dielectric film 33 having a dielectric constant higher than that of air. Therefore, the actual length related to radio wave transmission from the support surface 31 to the upper end of the waveguide structure 20 is longer than when the opening 21 is an empty space. As a result, the excellent effect of increased attenuation of radio waves by the waveguide structure 20 can be obtained.

[0078] Next, a variation of the third embodiment will be described. In the third embodiment, the plurality of conductor posts 22 are connected to the ground plane 32, but they may not be connected to the ground plane 32. Furthermore, in the third embodiment, the upper ends of the plurality of conductor posts 22 are connected to each other by conductor patterns 23, but the plurality of conductor posts 22 may also be electrically connected to each other in the middle portion between the upper and lower ends using an inner lattice-like conductor pattern. By connecting the plurality of conductor posts 22 to each other in the middle portion, the function as a unit waveguide can be improved.

[0079] [Fourth Embodiment]

[0080] Next, refer to Figure 8 The communication device of the fourth embodiment will be described below. Hereinafter, the communication device compared to the first embodiment (…) Figure 1A , Figure 1B , Figure 1C The same composition is omitted.

[0081] Figure 8 This is a cross-sectional view of the communication device according to the fourth embodiment. In the first embodiment, the first antenna 11 and the second antenna 12 are disposed on a common module substrate 30. Figure 1B In this embodiment, the module substrate 30 serves as a support component for the first antenna 11 and the second antenna 12. In contrast, in the fourth embodiment, the first antenna 11 and the second antenna 12 are formed on different first module substrates 30A and 30B, respectively. The first module substrate 30A and the second module substrate 30B each have an internal ground plane 32A and a ground plane 32B. The waveguide structure 20 is fixed to the second module substrate 30B.

[0082] The first module substrate 30A and the second module substrate 30B are fixed to the support surface 36 of the common support member 35. The support member 35 is housed within the housing 50 and is fixed relative to the housing.

[0083] Next, the superior effects of the fourth embodiment will be explained. In the fourth embodiment, by configuring the waveguide structure 20, the same superior effects as in the first embodiment can be obtained. Furthermore, in the fourth embodiment, the first antenna 11 and the second antenna 12 are formed on different module substrates, thus increasing the flexibility in their configuration.

[0084] [Fifth Embodiment]

[0085] Next, refer to Figure 9A as well as Figure 9B The communication device of the fifth embodiment will be described below. Hereinafter, it will be compared with the first embodiment (…). Figure 1A ) and the second embodiment ( Figure 6A The configuration of the communication device is the same as that of the other two devices, so the description is omitted.

[0086] Figure 9A This is a top view of the communication device according to the fifth embodiment. Figure 9B yes Figure 9A A cross-sectional view along the dashed line 9B-9B. In the first embodiment ( Figure 1A In the first embodiment, multiple openings 21 of the lattice-shaped metal wall constituting the waveguide structure 20 correspond one-to-one with multiple second radiating elements 12a of the second antenna 12. In contrast, in the fifth embodiment, two openings of the lattice-shaped metal wall constituting the waveguide structure 20 correspond to one second radiating element 12a. That is, two unit waveguides are arranged for one second radiating element 12a. Viewed from above, the metal wall along the column direction (in...) Figure 9A The straight section extending longitudinally passes through the center of each of the second radiating elements 12a.

[0087] In the fifth embodiment, similar to the first and second embodiments, the waveguide structure 20 attenuates radio waves of the fundamental frequency radiated from the first antenna 11. Radio waves of frequencies transmitted or received by the second antenna 12 are hardly attenuated in the waveguide structure 20.

[0088] Next, the superior effects of the fifth embodiment will be explained. In the fifth embodiment, similar to the first and second embodiments, the waveguide structure 20 allows the radiation from the first antenna 11 to be reflected by the electromagnetic wave reflector 60. Figure 4 The radio waves reflected and incident on the second antenna 12 at their fundamental frequency are attenuated. Therefore, the input to the low-noise amplifier 87 is reduced. Figure 2 The signal is at its fundamental frequency. As a result, the signal strength of higher harmonic components generated by the nonlinearity of the low-noise amplifier 87 is also reduced. Therefore, the influence of noise caused by radio waves radiated from the first antenna 11 on the signals transmitted and received by the second antenna 12 can be reduced.

[0089] Furthermore, in the fifth embodiment, the relative positional relationship between the plurality of unit waveguides included in the waveguide structure 20 and the plurality of second radiating elements 12a of the second antenna 12 is also the same in all the second radiating elements 12a. Therefore, it is possible to suppress the antenna gain deviation of a single second radiating element 12a.

[0090] In the fifth embodiment, Figure 9A In the second radiating element 12a of the second antenna 12, the top and bottom edges intersect the metal wall, while the left and right edges do not. In this case, it is preferable to excite the second radiating element 12a so that the edges that do not intersect the metal wall become wave sources. That is, it is preferable to... Figure 9A The polarization direction of the second radiating element 12a is left-right.

[0091] Next, a variation of the fifth embodiment will be described.

[0092] In the fifth embodiment, when viewed from above, the straight portion of the metal wall extending along the column direction passes through the center of the second radiating element 12a; however, the straight portion of the metal wall extending along the row direction may also pass through the center of the second radiating element 12a. Furthermore, in the fifth embodiment, two unit waveguides are associated with one second radiating element 12a; however, three or more unit waveguides may also be associated with one second radiating element 12a.

[0093] [Sixth Embodiment]

[0094] Next, refer to Figure 10A as well as Figure 10B The communication device of the sixth embodiment will be described below. Hereinafter, the communication device compared to the fifth embodiment (…) Figure 9A , Figure 9B The same composition is omitted.

[0095] Figure 10A This is a top view of the communication device according to the sixth embodiment. Figure 10B yes Figure 10A The cross-sectional view along the dashed line 10B-10B. In the fifth embodiment, two unit waveguides are associated with one second radiating element 12a. In contrast, in the sixth embodiment, one unit waveguide is associated with two second radiating elements 12a. Specifically, one unit waveguide is configured for two second radiating elements 12a arranged in the row direction. The top view of each unit waveguide is a rectangle longer in the row direction, and in top view, the two second radiating elements 12a are contained within one unit waveguide.

[0096] In the sixth embodiment, similar to the fifth embodiment, the waveguide structure 20 attenuates radio waves of the fundamental frequency radiated from the first antenna 11. Radio waves of frequencies transmitted or received by the second antenna 12 are hardly attenuated in the waveguide structure 20.

[0097] Next, the superior effects of the sixth embodiment will be explained. In the sixth embodiment, as in the fifth embodiment, the influence of noise caused by radio waves radiated from the first antenna 11 on the signals transmitted and received by the second antenna 12 can be reduced.

[0098] Next, a variation of the sixth embodiment will be described. In the sixth embodiment, two second radiating elements 12a are associated with one unit waveguide, but it is also possible to associate three or more second radiating elements 12a with one unit waveguide. For example, in a top view, three or more second radiating elements 12a may be contained within one unit waveguide.

[0099] [Seventh Embodiment]

[0100] Next, refer to Figure 11A as well as Figure 11B The communication device of the seventh embodiment will be described below. Hereinafter, the communication device compared to the first embodiment (…) Figures 1A to 5 The same composition is omitted.

[0101] Figure 11A This is a top view of the communication device according to the seventh embodiment. Figure 11B yes Figure 11A The cross-sectional view along the dashed line 11B-11B. The communication device according to the seventh embodiment is similar to that of the first embodiment, having a waveguide structure 20 that includes a unit waveguide disposed in the path of radio waves received by the second antenna 12. Furthermore, the waveguide structure 20 is disposed outside the range of the half-value angle of the main beam when viewed from the first antenna 11. As the waveguide structure 20, a structure having waveguide functionality that significantly attenuates radio waves at the operating frequency of the first antenna 11 compared to the operating frequency of the second antenna 12 can be used.

[0102] The superior effects of the seventh embodiment will now be explained. In the seventh embodiment, as in the first embodiment, the influence of noise caused by radio waves radiated from the first antenna 11 on the signals transmitted and received by the second antenna 12 can be reduced.

[0103] The above embodiments are illustrative examples; of course, different substitutions or combinations of the structures shown in the embodiments are possible. The same effects resulting from the same structures in multiple embodiments are not mentioned sequentially in each embodiment. Furthermore, the present invention is not limited to the above embodiments. For example, those skilled in the art will recognize that various changes, improvements, and combinations are possible.

[0104] Explanation of reference numerals in the attached figures

[0105] 11…First antenna, 11a…First radiating element, 12…Second antenna, 12a…Second radiating element, 12R…Second antenna for receiving, 12T…Second antenna for transmitting, 20…Waveguide structure, 21…Opening, 22…Conductor post, 23…Conductor pattern, 30…Module substrate, 30A…First module substrate, 30B…Second module substrate, 31…Support surface, 32, 32A, 32B…Ground plane, 33…Dielectric film, 35…Support member, 36…Support surface, 41…First transmitting / receiving circuit, 42…Second transmitting / receiving circuit, 50…Housing, 6 0…Radio wave reflector, 80…Signal processing circuit, 81…Local oscillator, 82…Transmitter processing unit, 83…Switch, 84…Power amplifier, 85…Receiver processing unit, 86…Mixer, 87…Low-noise amplifier, 90…High-frequency integrated circuit element, 91…Intermediate frequency amplifier, 92…Mixer for up / down conversion, 93…Transmit / receive switch, 94…Power divider, 95…Phase shifter, 96…Attenuator, 97…Transmit / receive switch, 98…Power amplifier, 99…Low-noise amplifier, 100…Transmit / receive switch, 110…Baseband integrated circuit element.

Claims

1. A communication device, wherein, It has a first antenna, a second antenna, and a waveguide structure housed in the same housing. The operating frequency of the second antenna is higher than that of the first antenna. The aforementioned second antenna is an array antenna containing multiple radiating elements. The aforementioned waveguide structure includes a unit waveguide that significantly attenuates the radio waves at the operating frequency of the first antenna compared to those at the operating frequency of the second antenna. The unit waveguide, when viewed from the first antenna, is located outside the half-value angle range of the main beam and is positioned along the path of the radio waves received by the second antenna. The aforementioned waveguide structure comprises a plurality of the aforementioned unit waveguides, each of which is configured corresponding to each of the plurality of radiating elements of the aforementioned second antenna.

2. The communication device according to claim 1, wherein, It also includes a support component that supports the first antenna and the second antenna on a common support surface. When viewed from above, the waveguide structure does not overlap with the first antenna and includes the second antenna.

3. The communication device according to claim 2, wherein, The aforementioned waveguide structure includes a metal wall arranged in a lattice pattern when viewed from above, wherein portions of the plurality of openings surrounding the lattice-shaped metal wall constitute the aforementioned unit waveguide.

4. The communication device according to claim 2 or 3, wherein, A portion of the aforementioned housing is spaced apart from the aforementioned support surface, and the aforementioned waveguide structure is fixed to the aforementioned housing.

5. The communication device according to claim 2 or 3, wherein, The aforementioned waveguide structure is fixed to the aforementioned support component.

6. The communication device according to claim 2, wherein, It also includes a dielectric film disposed on the aforementioned support surface and covering the aforementioned second antenna. The aforementioned waveguide structure includes a plurality of conductor pillars embedded in the aforementioned dielectric film. When viewed from above, the plurality of conductor pillars are arranged along a grid-like straight line group. The plurality of conductor pillars surrounding the plurality of openings of the grid formed by the plurality of conductor pillars constitute the aforementioned unit waveguide.

7. The communication device according to claim 6, wherein, The aforementioned waveguide structure also includes a conductor pattern that connects the plurality of conductor pillars and is configured not to overlap with the plurality of radiating elements of the aforementioned second antenna when viewed from above.

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