Communication device and communication device control method

Abstract

The present invention provides a communication device for transmitting and / or receiving, with high gain and a high S / N ratio, electromagnetic waves in a high frequency band such as a band in the range of hundreds of GHz to terahertz, and a communication device control method capable of improving the gain and the S / N ratio of electromagnetic waves to be transmitted and / or received.　The communication device of the present disclosure is provided with an electric circuit that is a transmission circuit and / or a reception circuit, an antenna element, and a spatial filter disposed at a predetermined interval from the antenna element. The communication device has a position adjustment element capable of adjusting the interval between the spatial filter and the antenna element.

Description

Communication device and control method for communication device

[0006] , ,

[0001] The present disclosure relates to a communication device that transmits and / or receives electromagnetic waves at high frequencies of several hundred GHz or more, and to a communication device and a control method for the communication device that can improve the gain and signal-to-noise ratio of the transmitted and received electromagnetic waves by adjusting the position of a spatial filter arranged in front of a transmitting antenna and / or a receiving antenna.

[0002] In recent years, the use of electromagnetic waves in the millimeter wave band (about 30 to about 300 gigahertz (GHz)) has been progressing in mobile communications such as mobile phones, wireless LANs, and toll collection systems (ETC). Further, with the accompanying evolution of the communication environment and the spread of IoT, the development of devices for Beyond 5G and 6G communications is required, and research on technologies using electromagnetic waves having frequencies in the terahertz (THz, 1000 GHz or more) band is also progressing.

[0003] Thus, as the frequency of the electromagnetic waves to be used increases, a specific material corresponding to high-frequency electromagnetic waves is required for noise countermeasures and electromagnetic wave leakage prevention of a transmitter or receiver equipped with an antenna circuit. In particular, in a device that handles electromagnetic waves in the range from several hundred gigahertz to the terahertz band, location dependence cannot be ignored in all of the materials used, such as the conductive wires, circuit boards, and exterior members within the circuit, and precise adjustment of length, size, and thickness and design are required.

[0004] Conventionally, as a cover (radome) for housing a millimeter wave radar device that uses electromagnetic waves in the millimeter wave band, in order to shield electromagnetic waves of unnecessary frequencies while allowing good transmission of electromagnetic waves of the frequencies used as a radar, a structure in which a first constituent material made of a mesh formed of metal or a conductive polymer and a second constituent material made of a dielectric material are laminated has been proposed (Patent Document 1).

[0005] International Publication No. WO2018 / 047937

[0006] By using the cover for a millimeter wave radar of Patent Document 1 as a radome, it is possible to prevent electromagnetic waves of an undesired frequency from affecting the antenna circuit within the radar device and reducing the detection accuracy of the radar.

[0007] However, radar systems using the conventional radar covers described above only prevent a decrease in the signal-to-noise ratio (S / N ratio) of transmitted and received electromagnetic waves due to the influence of unwanted external electromagnetic waves, and do not perform the function of improving the gain or S / N ratio of electromagnetic waves transmitted and received from the radar system.

[0008] This disclosure aims to solve the above problems and to realize a communication device that transmits and / or receives electromagnetic waves in a high frequency band from several hundred GHz to the terahertz band, which improves the gain and signal-to-noise ratio of the transmitted and / or received electromagnetic waves, and a control method for a communication device that can improve the gain and signal-to-noise ratio of the transmitted and / or received electromagnetic waves.

[0009] To solve the above problems, the communication device disclosed in this application is a communication device comprising an electrical circuit which is a transmitting circuit and / or a receiving circuit, an antenna element, and a spatial filter which is arranged at a predetermined distance from the antenna element, characterized in that it has a position adjustment element which can adjust the distance between the spatial filter and the antenna element.

[0010] Furthermore, the control method for a communication device disclosed in this application is a control method for a communication device comprising an electrical circuit which is a transmitting circuit and / or a receiving circuit, an antenna element, and a spatial filter which is arranged at a predetermined distance from the antenna element, characterized in that the signal-to-noise ratio of electromagnetic waves transmitted from the communication device and / or the signal-to-noise ratio of electromagnetic waves received by the communication device is improved by changing the distance between the antenna element and the spatial filter using the position adjustment element.

[0011] The communication device disclosed herein can improve the gain and signal-to-noise ratio of transmitted and received electromagnetic waves without increasing the transmission and reception power by adjusting the distance between the antenna element and the spatial filter positioned in front of it using a position adjustment element, thereby adjusting the phase of the electromagnetic waves that are reflected multiple times between the spatial filter and the electrical circuit portion including the antenna element.

[0012] Furthermore, the control method for the communication device disclosed herein can increase the gain and signal-to-noise ratio of the transmitted and received electromagnetic waves by adjusting the distance between the antenna element and the spatial filter using a position adjustment element.

[0013] This is an illustrative diagram illustrating the configuration of a transceiver, which is a communication device according to this embodiment. This is an illustrative diagram illustrating the configuration of the communication device according to this embodiment and the multiple reflection of electromagnetic waves. This is a diagram illustrating the distance characteristics of the reception gain due to electromagnetic waves reflected by the ground. This is a diagram showing the cross-sectional configuration of a bandpass filter used in the communication device according to this embodiment. This is a diagram illustrating the configuration of the metal layer of a bandpass filter used in the communication device according to this embodiment. This is an illustrative diagram illustrating the impedance adjustment effect of the transmitting and receiving circuit in the communication device according to this embodiment.

[0014] The communication device disclosed herein comprises an electrical circuit which is a transmitting circuit and / or a receiving circuit, an antenna element, and a spatial filter which is arranged at a predetermined distance from the antenna element, and further comprises a position adjustment element which can adjust the distance between the spatial filter and the antenna element.

[0015] With this configuration, the communication device disclosed in this application can optimize the distance between the antenna element and the spatial filter using a position adjustment element, thereby controlling the multiple reflections of electromagnetic waves by the spatial filter to further emphasize the transmitted and received electromagnetic waves, and improving the signal-to-noise ratio of electromagnetic waves without increasing the transmission and reception output.

[0016] In the communication device disclosed in the present application, it is preferable that a reflective member that reflects electromagnetic waves is arranged between the antenna element and the spatial filter. By doing so, multiple reflections of the transmitted and received electromagnetic waves can be effectively generated, thereby more effectively improving the gain and signal-to-noise ratio of the electromagnetic waves.

[0017] Furthermore, it is preferable to further provide the electromagnetic wave radiating surface and / or electromagnetic wave incident surface of the communication device with a low-loss radome that covers the electrical circuit, the antenna element, the spatial filter, and the position adjustment element. In this way, the entire communication device, including the spatial filter whose position is changed by the position control element, can be protected from external interference.

[0018] Furthermore, it is preferable that the spatial filter is a bandpass filter configured as a laminate of a metal layer having a repeating pattern formed on it and a dielectric layer. In this way, the spatial filter can be positioned as a protective member with reduced influence on transmitted electromagnetic waves.

[0019] Furthermore, it is preferable that the communication device is a transceiver comprising a transmitter equipped with the transmitting circuit, the antenna element, the spatial filter, and the position adjustment element, and a receiver equipped with the receiving circuit, the antenna element, the spatial filter, and the position adjustment element. By doing so, the signal-to-noise ratio of electromagnetic waves can be improved in both the transmitter on the transmitting side and the receiver on the receiving side, enabling highly accurate communication.

[0020] Furthermore, it is preferable that the position adjustment element is an electric actuator.

[0021] The control method for a communication device disclosed herein is a control method for a communication device comprising an electrical circuit which is a transmitting circuit and / or a receiving circuit, an antenna element, and a spatial filter which is arranged at a predetermined distance from the antenna element, wherein the position adjustment element changes the distance between the antenna element and the spatial filter to improve the signal-to-noise ratio of electromagnetic waves transmitted from the communication device and / or the signal-to-noise ratio of electromagnetic waves received by the communication device.

[0022] In this way, the control method for communication devices disclosed in this application enables the transmission and reception of electromagnetic waves in a state in which the gain and signal-to-noise ratio are greater depending on the frequency of the electromagnetic waves used and the distance between communication devices.

[0023] The communication device and control method for the communication device disclosed in this application will be described below with reference to the drawings.

[0024] (Embodiment) Figure 1 is an illustrative diagram showing the schematic configuration of a transceiver consisting of a transmitter and a receiver, as described in this embodiment.

[0025] As shown in Figure 1, the transceiver 100 in this embodiment consists of a transmitter 10 that transmits electromagnetic waves and a receiver 20 that receives electromagnetic waves.

[0026] The transmitter 10 comprises an electrical circuit which is a transmitting circuit 11, an input terminal 12 into which the electrical signal to be transmitted is input to the transmitting circuit 11, a horn antenna 13 which serves as a transmitting antenna, and a bandpass filter 14 which is a spatial filter positioned in front of the electromagnetic wave emission end, which is the open end of the horn antenna 13. A low-loss radome 15 is also positioned to cover the entire transmitting circuit 11, horn antenna 13, and bandpass filter 14 that constitute the transmitter 10.

[0027] Furthermore, the receiver 20 that constitutes the transceiver 100 illustrated in this embodiment includes an electrical circuit which is a receiving circuit 21, an output terminal 22 to which the received electrical signal is output from the receiving circuit 21, a horn antenna 23 as a receiving antenna, and a bandpass filter 24 which is a spatial filter positioned in front of the electromagnetic wave incident end, which is the open end of the horn antenna 23. Similar to the transmitter 10, a low-loss radome 25 is positioned to cover the entire receiving circuit 21, horn antenna 23, and bandpass filter 24 that constitute the receiver 20.

[0028] As shown in Figure 1, the transmitter 10 and receiver 20 that constitute the transceiver 100 illustrated in this embodiment have their electromagnetic wave emission and incidence ends positioned at a predetermined distance from each other. Although the electrical circuits of the transmitting circuit 11 and the receiving circuit 21 have different functions, their main configurations are similar. For this reason, the configuration of the transmitter 10 will be described below as representative of the communication device disclosed in this application. Although there is a difference in that electromagnetic waves are transmitted and electromagnetic waves are received, the configuration of the receiver 20 described in this embodiment is the same as the configuration of the transmitter 10 described below.

[0029] Figure 2 is an illustrative diagram showing the cross-sectional configuration of the transmitter described in this embodiment.

[0030] As shown in Figure 2, the transmitter 10 of the transceiver 100 shown in this embodiment includes a transmitting circuit 11 consisting of an antenna circuit 11a that generates electromagnetic waves to be transmitted, an electronic device 11b such as an IC chip for transmitting electromagnetic waves, and a circuit board 11c on which a predetermined circuit pattern is formed. In Figure 2, an electrical signal input from an input terminal 12 (see Figure 1), which is not shown, is converted into a predetermined waveform by the transmitting circuit 11, and the output is amplified as appropriate and radiated from the electromagnetic wave radiating portion of the antenna circuit 11a.

[0031] Furthermore, there are no particular restrictions on the transmission circuit 11 of the communication device 10 according to this embodiment, and any well-known transmission circuit that can be used to transmit electromagnetic waves of high frequencies of several hundred GHz or more can be employed.

[0032] The electromagnetic waves, which are transmitted waves radiated from the antenna circuit 11a, have their directivity enhanced as they pass through the waveguide portion 13b and the cone-shaped portion 13a of the horn antenna 13, and are radiated toward the front side of the horn antenna 13 (to the right in Figure 2).

[0033] A bandpass filter 14, which is a spatial filter that selectively transmits a predetermined frequency while shielding most electromagnetic waves of other frequencies, is positioned in front of the electromagnetic wave radiating end of the horn antenna 13. The bandpass filter 14 is located on the front side (electromagnetic wave radiating side) of the horn antenna 13 and can also function as a radome to protect the antenna element 13 and the electrical circuit 11.

[0034] Here, the bandpass filter 13 is designed to transmit electromagnetic waves of a frequency emitted from the transmitting circuit 11 through the horn antenna 13 with minimal attenuation, by having a structure in which a dielectric layer and a metal layer, which will be described later, are stacked.

[0035] Furthermore, in the transmitter 10 of the transceiver 100 described in this embodiment, an electric actuator 16 is provided as a position adjustment element that can change the distance ΔG (see Figure 2) between the bandpass filter 14 and the front end of the horn antenna 13.

[0036] In the transmitter 10 of the transceiver 100 shown in this embodiment, the gain and signal-to-noise ratio of the electromagnetic waves transmitted from the transmitter 10 can be improved by adjusting the distance ΔG between the bandpass filter 15 and the horn antenna 13 using the actuator 16.

[0037] Most of the transmitted electromagnetic waves radiated from the horn antenna 13, indicated by the symbol A in Figure 2, pass through the bandpass filter 14 and are radiated to the receiver 20 (not shown) located in front (right side in Figure 2). On the other hand, the components of the transmitted electromagnetic waves reflected by the bandpass filter 14 are reflected by the horn antenna 13 and the reflector 17 placed inside the transmitter, and are radiated in the same direction as the radiation direction of the transmitted electromagnetic waves, as indicated by the symbol B in Figure 2. Note that this reflection of electromagnetic waves by the bandpass filter 14 and the horn antenna 13 and reflector 17 is not limited to a single reflection as shown in Figure 2, but occurs repeatedly as multiple reflections.

[0038] Figure 3 shows the distance characteristics of the received power gain due to ground reflection of electromagnetic waves transmitted from a transmitter and reaching a receiver located at a predetermined distance.

[0039] The distance characteristics of the received power gain shown in Figure 3 illustrate the change in received power gain (dB) with respect to horizontal distance (m) when electromagnetic waves with a frequency of 2.0 GHz transmitted from a transmitting antenna at a height of 5.0 m are received by a receiving antenna at a height of 1.65 m. Note that since electromagnetic waves transmitted from the transmitting antenna travel in two ways—directly and reflected by the ground—the effective distance between the antennas differs, causing interference and changing the received power gain.

[0040] As shown in Figure 3, the gain 31 of the electromagnetic wave received by the receiving antenna changes significantly due to interference between the directly transmitted electromagnetic wave and the electromagnetic wave transmitted via reflection from the ground, which occurs depending on the distance between the transmitting and receiving antennas. This is in contrast to the received power gain 32, which gradually decreases with distance when reflection from the ground is not considered. Looking at the distance characteristics of the received power gain 31 of the electromagnetic wave affected by interference from the ground-reflected wave, we see that there are multiple points where the gain drops significantly due to interference, and at distances between these points, the received power gain 31 affected by interference is greater than the received power gain 32 of the directly transmitted electromagnetic wave. This indicates that, depending on the distance between the transmitter and receiver, the gain of the transmitted and received electromagnetic waves may improve due to the interference of reflected waves.

[0041] The communication device disclosed in this application utilizes the change in electromagnetic wave gain caused by the interference between electromagnetic waves with different phases due to different propagation distances, as explained in Figure 3, to improve the gain of the electromagnetic wave transmitted from the transmitter and received by the receiver, and to increase its signal-to-noise ratio. In the portion shown in Figure 3 where the received power gain is improved due to the interference of reflected waves, it is assumed that the phase difference between the directly propagating electromagnetic wave and the reflected wave is 0° (an integer multiple of 360°). Therefore, the reflection conditions inside the transmitter are adjusted and controlled so that the phase relationship between the main transmitted electromagnetic wave and the reflected electromagnetic wave becomes such that the power gain is increased.

[0042] Furthermore, the change in power gain due to the interference of electromagnetic waves with different phases can be generated more effectively by the interference of a greater number of electromagnetic waves with different phases. In addition, the interference between electromagnetic waves generated by adjusting the distance between the bandpass filter 14, which is an electromagnetic wave reflecting component, and the horn antenna 13 can be adjusted more efficiently by the presence of a greater number of electromagnetic waves with different transmission and reception distances. For this reason, as shown in Figure 2, it is preferable to place a reflector 17 that reflects electromagnetic waves near the horn antenna 13, which is an antenna element, to effectively generate multiple reflections between it and the bandpass filter 14.

[0043] In addition, as a member for reflecting electromagnetic waves, in addition to the reflector 17 illustrated in FIG. 2, antenna elements such as the horn antenna 13, or a coating of a conductive material such as metal in a region where the influence of the transmission / reception circuit portion does not occur, etc., as long as it is a member that can reflect the electromagnetic waves reflected by the band-pass filter 14 back to the side where the band-pass filter 14 is disposed, various types can be used. Also, in the case where the antenna element is made of metal like the horn antenna 13, since there may be a case where it is not necessary to dispose a reflecting member such as the reflector 17, adding and disposing a reflecting member for reflecting the electromagnetic waves reflected by the spatial filter 14 is not an essential requirement in the invention disclosed in the present application.

[0044] The low-loss radome 15 illustrated in FIG. 1 is a member for protecting various members disposed inside the transmitter 10 including the band-pass filter 14 whose position changes with respect to the horn antenna 13 from external interference, particularly physical interference. For this reason, when the transmission circuit 11, the horn antenna 13, etc. are disposed and protected inside the housing, etc., if it is in a state where it is not affected by external physical interference or external influences such as water droplets and dust, a protective member such as the low-loss radome 15 that covers the whole is not necessary. Also, it is important that the low-loss radome 15 is composed of low-loss members such as ceramics with a low dielectric constant such as alumina, sapphire, PET (polyethylene terephthalate), COP (cycloolefin polymer), etc., so that the loss of the transmitted electromagnetic waves is minimized and the influence on the electromagnetic waves transmitted from the transmitter is as small as possible.

[0045] FIG. 4 is a cross-sectional view showing the configuration of the band-pass filter included in the transmitter exemplified in the present embodiment.

[0046] The band-pass filter 14 included in the transmitter shown in the present embodiment is configured by sequentially laminating a first dielectric layer 14a, a metal layer 14b, and a second dielectric layer 14c from the electromagnetic wave incident surface side indicated by the white arrow in FIG. 4.

[0047] The film thickness D1 of the first dielectric layer 14a and the film thickness D2 of the second dielectric layer 14c of the band-pass filter 14 shown in FIG. 4 both satisfy the requirements of the following (Equation 1) as an example. D = λ / 4√ε ± 20% (Equation 1) (However, λ = center wavelength of electromagnetic wave, ε = dielectric constant of dielectric layer).

[0048] Further, the metal layer 14b used for the band-pass filter 14 in the transmitter according to the present embodiment has a mesh structure formed in a thin film shape.

[0049] The first dielectric layer 14a and the second dielectric layer 14c of the band-pass filter 14 can both be formed of various dielectrics such as acrylic resin, silicone resin, urethane resin, etc. In addition to these, dielectric materials such as silicone rubber, titanium oxide, polyvinylidene fluoride, polyester resin, glass, silicone rubber, etc. can also be used.

[0050] Note that the first dielectric layer 14a and the second dielectric layer 14c can both be formed as a single-layer structure formed of one type of material. Also, a structure in which two or more layers of the same or different materials are laminated can be adopted. Furthermore, the first dielectric layer 14a and the second dielectric layer 14c can be formed using the same dielectric material, and it is also possible to configure them using different dielectric materials including the number of layer structures thereof.

[0051] When a resin base material is used to form the metal layer 14b which is a thin film, this base material will be included in the first dielectric layer 14a or the second dielectric layer 14c.

[0052] As described above, the thickness D1 of the first dielectric layer 14a and the thickness D2 of the second dielectric layer 14c are both within the range obtained by D = λ / 4√ε ± 20% (Equation 1) in consideration of the dielectric constant ε of the dielectric members constituting the respective dielectric layers 14a and 14c based on the wavelength λ of the electromagnetic wave transmitted by the band-pass filter 14.

[0053] More specifically, when the center frequency of the electromagnetic wave to be transmitted is between 100 GHz and 400 GHz, it is preferable to use a general dielectric material with a relative permittivity of about 2 to 3 for the first dielectric layer 14a and the second dielectric layer 14c, and to set their thickness to 120 μm to 230 μm.

[0054] In the bandpass filter 14 used in the transmitter of this embodiment, both the first dielectric layer 14a and the second dielectric layer 14c are made of an acrylic-based OCA (Optical Clear Adhesive) that is translucent and adhesive. This improves workability and reduces material consumption in the fabrication of the bandpass filter 14 in which the first dielectric layer 14a and the second dielectric layer 14c are laminated with a metal layer 14b in between, making it possible to realize the bandpass filter 14 easily and at low cost.

[0055] When using self-adhesive resin materials such as OCA as the first dielectric layer 14a and the second dielectric layer 14c, it is preferable that the adhesive force to the metal layer 14b be 3 N / 10 mm or more.

[0056] Of course, the laminated structure of the first dielectric layer 14a, the metal layer 14b, and the second dielectric layer 14c can also be constructed using adhesive materials such as double-sided adhesive sheets or adhesives.

[0057] The metal layer 14b of the bandpass filter 14 is a thin film layer positioned between the first dielectric layer 14a and the second dielectric layer 14c, and has a lattice-like mesh structure made of a metal material formed on a resin substrate.

[0058] The surface resistance of the metal layer 14b is preferably 60 Ω / □ or less. If the surface resistance is higher than 60 Ω / □, it becomes difficult to obtain selectively high transmission characteristics for electromagnetic waves of the desired frequency. From the viewpoint of electromagnetic wave transmission characteristics, a lower lower limit for the surface resistance is preferable, ideally 0 Ω / □, but considering the manufacturing problems of realizing the pattern shape of the thin film, it is preferable to have a value of about 0.01 Ω / □.

[0059] Furthermore, by making the thickness of the metal layer 14b so thin that it is negligible as a "layer" compared to the thicknesses D1 and D2 of the stacked first dielectric layer 14a and second dielectric layer 14c, it is possible to reduce transmission loss. For this reason, the thickness of the metal layer 14b is preferably 5 μm or less, and more preferably 3 μm or less.

[0060] The metal layer 14b can be formed using inorganic conductive materials such as ITO (indium tin oxide), ATO (antimond-doped tin oxide), and carbon black; organic conductive materials such as PEDOT-PSS, polyacetylene, and polythiophene; and metal plating films such as electroless plating films and electrolytic plating films.

[0061] As a method for forming the metal layer 14b in a predetermined pattern, various conventionally known thin-film pattern formation methods can be used, such as various printing methods like inkjet printing and screen printing on a resin substrate such as polyethylene terephthalate (PET), a method in which a conductive material is applied to the entire surface of the substrate sheet, and then a mask is placed over the area where the metal layer 14b is to be formed, and the conductive material is removed from the uncovered areas using acid, or a method in which the conductive material is removed from the areas other than the metal layer 14b by irradiating them with laser light.

[0062] Furthermore, various resins including PET, rubber materials, and thin films of various dielectrics (insulators) such as paper and wood can be used as the substrate for the metal layer 14b.

[0063] Figure 5 is a schematic diagram showing the shape of the metal layer of the bandpass filter used in the transmitter illustrated in this embodiment.

[0064] As shown in Figure 5, the metal layer 14b of the bandpass filter 14 of the transmitter 10 shown in this embodiment is a mesh structure 14b1 formed by creating a grid pattern of conductive material on a PET substrate 14b2. For example, the repeating pitch of the mesh structure 14b1, i.e., the distance a between the centers of the lines constituting the mesh, is 0.70 mm in both the vertical and horizontal directions, the width b of the mesh opening is 0.63 mm, the line width c of the lines constituting the mesh is 35 μm, and the thickness is 1 μm. The surface resistance of the metal layer 14b in this case is 60 Ω / □.

[0065] In the bandpass filter 14 used in the transmitter shown in this embodiment, the thickness of the first dielectric layer 14a and the second dielectric layer 14b can be determined using the above-described formula 1, thereby providing low loss by transmitting more electromagnetic waves near the frequency of the electromagnetic waves transmitted from the transmitter (target frequency) to the back side of the bandpass filter 14, and high reflection characteristics that effectively reflect electromagnetic waves at frequencies far from the target frequency. On the other hand, as described above, in the transmitter described in this embodiment, the electromagnetic waves reflected by the bandpass filter 14 are multiple-reflected, and the gain and S / N ratio of the transmitted electromagnetic waves are improved by the interference effect between electromagnetic waves having different phases. For this reason, it is preferable to adjust the electromagnetic wave transmission characteristics of the bandpass filter 14 so that a certain amount (for example, about 10%) of electromagnetic waves are reflected.

[0066] Furthermore, the electromagnetic waves reflected by this bandpass filter 14 may become noise components in relation to the transmitted electromagnetic waves. Therefore, in the transmitter 10 shown in this embodiment, it is crucial to adjust the distance between the horn antenna 13, which is an antenna element, and the bandpass filter 14 using the position adjustment element 16 while actually transmitting electromagnetic waves, in order to find the conditions under which the gain and signal-to-noise ratio of the electromagnetic waves are in an optimal state.

[0067] An electric actuator can be suitably used as the position adjustment element 16. In order to achieve miniaturization of the transmitter 10, it is preferable to use a smaller electric actuator 16, and for example, those used in artificial hearts or focusing units for camera lenses can be used well. When the center frequency of the bandpass filter 14 is several hundred GHz or higher, such as 300 GHz, it is desirable that the positioning accuracy (repeatability) required of the electric actuator 16 be 1 μm or less.

[0068] Furthermore, it is preferable that the position-holding power of the electric actuator 16 used is 20 mW or less, and the drive voltage is 12 V or less.

[0069] Specifically, in a transceiver 100 employing the bandpass filter 14 exemplified in Figures 4 and 5 above, a communication experiment using electromagnetic waves in the 300 GHz band was conducted. It was confirmed that by changing the position of the bandpass filter 14 using the electric actuator 16 and adjusting the distance ΔG (see Figure 2) between it and the horn antenna 13 within a range of 200 μm, a received power improvement effect of 1.8 dB was observed.

[0070] Furthermore, the transceiver 100 is equipped with an automatic position adjustment circuit that adjusts the operating voltage of the electric actuator 16 while understanding the signal-to-noise ratio of the electromagnetic waves being transmitted and received. This allows the bandpass filter 14 to be continuously positioned in a location that enables optimal electromagnetic communication in response to changes in the transmission and reception status of the transceiver 100, particularly the frequency of the electromagnetic waves used and the distance between the transmitter 10 and the receiver 20.

[0071] Furthermore, if the frequency of the electromagnetic waves used for transmission and reception, and the distance between the transmitter and receiver, do not change, the electric actuator 16 can be used to adjust the distance ΔG between the horn antenna 13 and the bandpass filter 14 to a preferred initial value, and the configuration can be made to maintain that ΔG value.

[0072] As described above, the transmitter 10 and receiver 20 constituting the transceiver 100 according to this embodiment are equipped with electric actuators 16 and 26, which are position adjustment elements that can adjust the distance (ΔG) between the horn antennas 13 and 23, which are transmitting antennas and receiving antennas, and the bandpass filters 14 and 24 arranged in the electromagnetic wave transmission and reception paths. By adjusting the distance ΔG to a preferred value, the power gain and S / N ratio can be improved without increasing the output of the transmitted and received electromagnetic waves.

[0073] (Other effects) The following describes further effects caused by electromagnetic waves reflected by the bandpass filter 14, which is a spatial filter.

[0074] Figure 6 is an illustrative diagram illustrating the impedance adjustment effect of the transmission circuit by electromagnetic waves reflected by a spatial filter in the transmitting device according to this embodiment.

[0075] Note that the configuration of the transmitting device 10 shown in Figure 6 is the same as that of the transmitting device 10 described using Figure 2 in the above embodiment, and therefore its description will be omitted.

[0076] Figure 2 illustrates the multiple reflections of the transmitted electromagnetic wave A reflected by the bandpass filter 14. However, the transmitted electromagnetic wave A reflected by the bandpass filter 14 also has a reflected wave that returns to the antenna circuit 11a via the horn antenna 13, as shown by the symbol C in Figure 6. When this reflected wave C enters the antenna circuit 11a, superposition and interference occur with the transmitted electromagnetic wave A at the antenna reference plane (symbol D), causing a change in the impedance of the antenna reference plane D.

[0077] In the transmitter 10 according to this embodiment, the position of the bandpass filter 14 that reflects the transmitted electromagnetic wave can be changed by the position adjustment element 16, so that the phase of the reflected wave on the antenna reference plane can be controlled and the impedance of the antenna circuit 11a can be adjusted.

[0078] In particular, when the loss between the antenna circuit 11a and the antenna element 13 is small, the characteristics of the antenna circuit 11 can be tuned and improved. The characteristics of the antenna circuit 11a change depending on the combination and performance variations of each component that makes up the circuit, so there are limits to improving the performance of the circuit characteristics in circuit design. However, in the transmitter 10 of this embodiment, the circuit characteristics can be adjusted by reflecting the electromagnetic waves actually transmitted from the antenna circuit 11a, which is extremely useful.

[0079] As described above, the gain and signal-to-noise ratio of the transmitted electromagnetic waves change by changing the distance between the bandpass filter 14 and the antenna element 13 using the position adjustment element 15. Therefore, it is preferable to determine the position of the bandpass filter 14 using the position adjustment element 15 in order to obtain better characteristics in conjunction with the characteristic adjustment of the antenna circuit 11a.

[0080] In the above embodiment, an example was described in which a bandpass filter, which transmits electromagnetic waves of a predetermined frequency and shields electromagnetic waves of other frequencies, was used as the spatial filter in the transmitter and receiver. However, in addition to bandpass filters, various other components with filtering functions that transmit electromagnetic waves of specific frequencies and shield electromagnetic waves of other frequencies, such as high-pass filters and low-pass filters, can be used as spatial filters.

[0081] In the above embodiment, the bandpass filter was exemplified as a metal mesh with a grid-like pattern, which is a metal layer having a repeating pattern made of a metal material disposed between the first dielectric layer and the second dielectric layer. However, the repeating pattern of the metal layer is not limited to the mesh configuration described above, and a resonant reflective layer can be used, which has multiple metal patterns having the property of reflecting electromagnetic waves of a predetermined frequency arranged in a planar manner. In this case, the repeating pattern can be a configuration in which multiple circular or rectangular ring-shaped patterns or rectangular patterns without openings (filled) are arranged in a vertical and horizontal matrix at predetermined intervals.

[0082] Furthermore, the dielectric and metal layers constituting the bandpass filter are not limited to the configuration exemplified above, in which a single metal layer is sandwiched between a first dielectric layer and a second dielectric layer. Various stacked configurations can be adopted, such as a two-layer configuration in which a metal layer is formed on one end face of a dielectric layer, a configuration in which metal layers are formed on both sides of a single dielectric layer, or a five-layer configuration in which the first dielectric layer, first metal layer, second dielectric layer, second metal layer, and third dielectric layer are stacked in sequence. When the bandpass filter comprises multiple metal layers, the conductive patterns formed on each metal layer may be the same or different.

[0083] Furthermore, in the above embodiment, an electric actuator was exemplified as a position adjustment element for adjusting the distance between the antenna element and the spatial filter. Various electric actuators, such as those using piezoelectric elements or solenoid actuators using electromagnets, can be used as position adjustment elements in the communication device disclosed in this application. In addition, various elements that can adjust and control the size of the distance between the antenna element and the spatial filter in accordance with an electrical signal can be used as position adjustment elements, such as a configuration that includes a pair of cylinder mechanisms whose thickness can be adjusted by a helical structure and an ultrasonic motor or various digital motors that can control the rotation of at least one of these cylinders by a predetermined angle.

[0084] Furthermore, although the above embodiment shows a configuration in which the position of the spatial filter is changed by a position adjustment element to adjust the distance from the antenna element, it is also possible to adopt a configuration in which the position adjustment element is placed on an electrical circuit board so that the position of the electrical circuit including the antenna element can be adjusted, thereby allowing the distance from the spatial filter to be adjusted.

[0085] Furthermore, although a horn antenna was used as an example for the antenna elements of the transmitter and receiver in the above embodiment, the antenna elements are not limited to horn antennas. Various antenna elements used for transmitting and receiving electromagnetic waves at high frequencies of several hundred GHz or more can be employed, such as patch antennas, monopole and dipole antennas with relatively low antenna gain, and array antennas of these antennas.

[0086] Furthermore, while the above embodiment exemplifies a transceiver equipped with a transmitter and a receiver as a communication device, the communication devices disclosed in this application can include various types of communication devices capable of transmitting or receiving electromagnetic waves of several hundred GHz or higher, such as a transmitting device only, a receiving device only, or a radar device equipped with a part that emits electromagnetic waves and a part that receives electromagnetic waves.

[0087] The communication device and adjustment method disclosed herein include a position adjustment element that can adjust the distance between the antenna element of the communication device and a spatial filter. By utilizing the reflection of electromagnetic waves at the spatial filter using this position adjustment element, the gain and signal-to-noise ratio of the electromagnetic waves used for communication can be improved without increasing the output power of the transmitted and received electromagnetic waves.

[0088] 10 Transmitter (communication device) 11 Transmitting circuit (electrical circuit) 13 Horn antenna (antenna element) 14 Bandpass filter (spatial filter) 16 Electric actuator (position adjustment element) 20 Receiver (communication device) 100 Transceiver (communication device)

Claims

1. A communication device comprising an electrical circuit which is a transmitting circuit and / or a receiving circuit, an antenna element, and a spatial filter which is positioned at a predetermined distance from the antenna element, characterized in that it has a position adjustment element which can adjust the distance between the spatial filter and the antenna element.

2. The communication device according to claim 1, wherein a reflective member that reflects electromagnetic waves is arranged between the antenna element and the spatial filter.

3. The communication device according to claim 1 or 2, further comprising a low-loss radome covering the electrical circuit, the antenna element, the spatial filter, and the position adjustment element on the electromagnetic wave radiating surface and / or the electromagnetic wave incident surface of the communication device.

4. The communication device according to any one of claims 1 to 3, wherein the spatial filter is a bandpass filter configured as a laminate of a metal layer having a repeating pattern formed of a metal material and a dielectric layer.

5. The communication device according to any one of claims 1 to 4, wherein the communication device is a transceiver comprising a transmitter having the transmitting circuit, the antenna element, the spatial filter, and the position adjustment element, and a receiver having the receiving circuit, the antenna element, the spatial filter, and the position adjustment element.

6. The communication device according to any one of claims 1 to 5, wherein the position adjustment element is an electric actuator.

7. A method for controlling a communication device comprising an electrical circuit which is a transmitting circuit and / or a receiving circuit, an antenna element, and a spatial filter which is positioned at a predetermined distance from the antenna element, characterized in that the signal-to-noise ratio of electromagnetic waves transmitted from the communication device and / or the signal-to-noise ratio of electromagnetic waves received by the communication device is improved by changing the distance between the antenna element and the spatial filter using the position adjustment element.

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