175 results about "Grating lobe" patented technology

The invention relates to a broadband planar array antenna light-operated beam forming method based on multi-task sparse learning, and the method comprises the steps: deducing an array factor expression of a broadband array as priori knowledge through employing a rectangular planar array antenna; constructing a multi-frequency-point beam joint optimization model of the planar array antenna based on the neural network; based on the priori knowledge, calculating a total loss function of the model by using expected broadband array pattern data and a group inhaul cable regularization method, and training a multi-frequency-spot beam joint optimization model; and based on the trained model, obtaining the optimal array layout and the amplitude and delay distribution of each array element, and calculating to obtain a low-sidelobe directional diagram in which the deflection angle is irrelevant to the frequency. According to the invention, the deflection angle of the array radiation beam is kept constant in a broadband range, and the problem of'beam squint 'of a traditional phased array is solved; and meanwhile, the beam sidelobe level of each frequency point is effectively suppressed, and the grating lobe problem of the uniform array on the broadband is avoided.

The invention discloses a millimeter wave circular polarization ridge gap waveguide antenna. The waveguide antenna comprises a feed waveguide layer, a waveguide gap layer, a grating lobe suppressor, a polarization converter and a radiation cavity layer which are sequentially stacked from bottom to top. The waveguide antenna adopts an interdigital ridge structure, so that electromagnetic wave leakage radiation can be effectively inhibited, the stability of the working mode of the antenna unit is ensured, and the isolation of the antenna in a large-scale array is enhanced; the feed waveguide layer and the waveguide slot layer are spliced to form the interdigital ridge structure, the production and assembly process is simple, the welding process is omitted, and the production cost is reduced; left-hand circular polarization or right-hand circular polarization can be switched on the polarization converter by changing the orientation of the cross-type gap. By feeding from the two ends of the feed waveguide layer, a dual-circular-polarization working mode can also be realized; by adjusting the size of each slot on the waveguide slot layer, the flexibility of grating lobe suppression can be improved, and the side lobe level of the antenna can be reduced. The invention relates to the technical field of antennas.

The invention relates to the technical field of array antennas, and discloses a common-caliber layout-based ultra-wideband array antenna, which comprises a low-frequency unit and a high-frequency unit which are arranged based on a common caliber, and is characterized in that the working frequency of the low-frequency unit covers an fmin-f0 frequency band, and the working frequency of the high-frequency unit covers an f0-fmax frequency band. The low-frequency unit is a broadband dual-polarized antenna, a uniform tight coupling array distributed at equal intervals is formed by adopting a tight coupling principle, and the unit interval is calculated based on a grating lobe suppression condition at the frequency f0. The high-frequency unit is a miniaturized broadband dual-polarized antenna and adopts a sparse array form; the initial unit spacing and the unit number of the sparse array are calculated based on the grating lobe suppression condition at the highest frequency f2 of the f1-f2 frequency band with the side lobe requirement between the f0-fmax frequency bands. The ultra-wideband array antenna gives consideration to full-band array performance, can provide sufficient space for active circuit arrangement, and effectively reduces power consumption and cost.

The invention discloses a non-line-of-sight moving target three-dimensional reconstruction method based on an MIMO millimeter wave radar, and is applied to the technical field of radar target detection in a complex urban environment. Aiming at the problem of difficulty in realizing three-dimensional reconstruction of a non-line-of-sight moving target in the existing radar target detection technology, the method comprises the following steps: firstly, establishing a non-line-of-sight multipath propagation model, and exporting a multipath signal model of an MIMO millimeter wave radar; the invention further provides a multipath signal departure angle (DoD) / arrival angle (DoA) unambiguous estimation algorithm, and solves the problem that a main lobe and a grating lobe are difficult to distinguish in the DoD / DoA estimation process of an existing commercial MIMO radar. And finally, proposing a path-oriented non-line-of-sight target three-dimensional positioning algorithm, respectively positioning the non-line-of-sight target by using different paths, and fusing different path positioning results to form a three-dimensional point cloud. According to the method, three-dimensional reconstruction of a plurality of non-line-of-sight moving targets can be realized, and the correlation problem between paths does not need to be considered.

The embodiment of the invention provides an antenna array, a radar, electronic equipment and a vehicle, and belongs to the technical field of antennas. Wherein the antenna array comprises a transmitting antenna array and a receiving antenna array. The transmitting antenna array and the receiving antenna array are used for forming a virtual array. The transmitting antenna array comprises at least two transmitting sub-arrays which are arranged at intervals in the first direction, and the distance between every two adjacent transmitting sub-arrays in the first direction is smaller than or equal to the aperture length of the receiving antenna array in the second direction. The receiving antenna array comprises at least two receiving sub-arrays arranged along the second direction, and each receiving sub-array comprises at least two receiving antennas arranged at intervals along the second direction. And the receiving antenna array satisfies the relational expression: 0 < dn-dn-1 < = 0.5 lambda. The antenna array provided by the embodiment of the invention has the characteristics of large array aperture, high resolution, no grating lobe and low side lobe.

The invention provides a distributed millimeter wave radar network-oriented DOA estimation method, a medium and equipment, and belongs to the technical field of radar signal processing. According to the method, after a large-aperture MIMO radar system is formed based on a plurality of small millimeter wave radars, a two-dimensional single-snapshot sparse array signal model is constructed by using a steering vector of a two-dimensional MIMO equivalent virtual plane array, and data interpolation and extrapolation processing are performed on aperture missing existing in a sparse array by constructing a block Hankel matrix and applying a matrix completion technology. On the basis, a fast two-dimensional angle estimation algorithm based on phase coherence factor weighting is adopted, and efficient joint estimation of the azimuth angle and the pitch angle of the target is achieved. The method can be flexibly applied to different types of distributed millimeter wave radar networks, effectively overcomes the interference effect of DOA estimation sidelobes and grating lobes in the prior art, and improves the signal-to-noise ratio level of array response.

A hybrid multiport array antenna comprises a plurality of columns of hybrid dipole unit cells, each of the hybrid dipole unit cells having a first dipole of a first type, and a second dipole of a second type, wherein the first dipole of the first type and the second dipole of the second type are configured to receive a single pair of RF (radio frequency) signals, the pair of RF signals having two orthogonal polarization states, wherein the first dipole of the first type and the second dipole of the second type are spaced with an offset in a vertical direction. The arrangement of the hybrid dipole unit cells reduces the phase center distance between the dipoles in each column and between columns, thereby assuring high gain while reducing grating lobes and other signal gain degradations caused by longer distances between phase centers.

A method and system for low Earth orbit (LEO) satellite multiple access and communication using grating lobes is disclosed. The method may include: acquiring ephemeris data for a plurality of LEO satellites; predicting an orbital trajectory for each of the plurality of LEO satellites based on the ephemeris data; selecting target satellites using the predicted orbital trajectories; adjusting an antenna array to form grating lobes in the directions of the selected target satellites; and transmitting and receiving data with the target satellites using the adjusted antenna array.

The invention provides an antenna system and a communication device, which can reduce the energy of grating lobes in an antenna array, is suitable for more scenes, and can be applied to communication scenes. The antenna system comprises a plurality of antenna units, and each antenna unit comprises a first antenna and a second antenna. The working mode of the first antenna comprises a high-order mode of a first frequency band, the working mode of the second antenna comprises a dominant mode of the first frequency band, and the first antenna and the second antenna are located in the same planar antenna array.

A quad-polarized antenna system according to the present invention comprises a plurality of RF chains, and an antenna array in which rows of first dual-polarized antenna units and rows of second dual-polarized antenna units are alternately arranged in a horizontal direction. The first dual-polarized antenna unit and the second dual-polarized antenna unit have different dual polarization characteristics from each other. The rows of first dual-polarized antenna units are used to form at least one first beam and at least one second beam which have + / −45° polarizations, and the rows of second dual-polarized antenna units are used to form at least one third beam and at least one fourth beam which have 0° / 90° polarizations. The first beam, the second beam, the third beam, and the fourth beam are formed towards different spatial directions, and the first and third beams correspond to main lobes, and the second and fourth beams correspond to grating lobes.

The invention discloses a beam training method, system and device for a near-field broadband XL-MIMO system based on grating lobes, and relates to the technical field of wireless communication. The method comprises the following steps: selecting a base station antenna spacing greater than half-wavelength, activating a corresponding antenna and connecting the antenna to a TTD element; designing a grating lobe generation and coverage mechanism based on the antenna spacing greater than half wavelength, and generating a codebook containing a user potential range area; and the pilot signals in the codebook are sequentially sent by the base station so as to carry out rough search. The position of the user is searched in two stages. In the rough search stage, a codebook based on grating lobes is designed in angle and distance dimensions by selecting a base station antenna spacing greater than half-wavelength and calculating TTD parameters, so that a plurality of potential user positions are determined. And in the accurate searching stage, the antenna spacing is recovered to the half wavelength, and the user position with the optimal gain is accurately identified according to the result of the rough searching stage, so that the final user position estimation is obtained.

The invention discloses a dual circularly polarized phased-array antenna based on triangular grid arrangement. A phased-array antenna module sub-array is formed by triangular grid arrangement of phased-array antenna units; the radiation unit adopts a cross oscillator with a gradual change structure, the impedance matching is improved, and a feed network of a three-branch linear bridge is matched, so that the impedance bandwidth of the antenna is improved, and the requirements of more communication frequency bands are met; the orthohexagonal antenna unit appearance and the metal partition wall are adopted, so that mutual coupling between the antenna units is reduced, and the isolation degree between the antenna units and the overall performance are improved; triangular grid arrangement is adopted, and the problems that the scanning range of a traditional rectangular array is limited, and grating lobes are prone to occurring during large-angle scanning are solved; the device has higher polarization purity and lower cross polarization level, supports quick splicing of N * N subarrays, and has the advantages of simple structure, low cost and easiness in processing.

The invention provides a beam forming optimization method for an ISAC system based on a reconfigurable antenna structure, and the method comprises the steps: firstly, designing an energy-saving DFBS based on a TTD reconfigurable antenna architecture based on a downlink terahertz large-scale MIMO ISAC system; the DFBS is switched between the modular MIMO and the uniform MIMO by dynamically controlling the antenna sub-arrays; in the sensing stage, modular MIMO is deployed, and a larger array aperture is realized by using fewer antennas; the beam dispersion effect at the main lobe and the grating lobe is utilized to realize rapid user perception; in the communication stage, uniform MIMO is adopted, and a TTD network is activated to reduce the near-field beam dispersion effect; then, based on the channel state information obtained in the sensing stage, proposing a joint optimization problem of analog / digital hybrid beam forming and TTD network delay so as to maximize a system sum rate; finally, analog beam forming and time delay are designed through a serial time delayer method, and then alternating iteration optimization solution is carried out on digital beam forming.

The present invention discloses a broadband dual-polarized slot hollow waveguide antenna, which includes a radiation slot layer, an H-polarization full-common-feed feeding network, an orthogonal mode separation layer, and a V-polarization full-common-feed feeding network stacked from top to bottom. The V-polarization full-common-feed feeding network adopts a bottom-feed feeding method to excite the radiation slot layer to generate vertically polarized waves. The H-polarization full-common-feed feeding network adopts a side-feed feeding method to cause the radiation slot layer to generate horizontally polarized waves. The orthogonal mode separation layer is designed based on a double-ridge rectangular waveguide cavity. The radiation slot layer is used to generate vertically polarized waves under the excitation of the V-polarization full-common-feed feeding network and horizontally polarized waves under the excitation of the H-polarization full-common-feed feeding network, and synthesize the vertically polarized waves and the horizontally polarized waves into cross-polarized waves and radiate them into free space. The advantages are that while having a relatively wide impedance bandwidth, the grating lobe level will not deteriorate significantly, and it has a high antenna efficiency and a high cross-polarization (XPD).

The invention discloses a device for inhibiting grating lobes of an acoustic transducer array by using band-pass driving signals, which comprises an upper computer, an acoustic host and an acoustic transducer array which are connected in sequence, the acoustic host comprises a logic control circuit, N direct digital synthesis circuits connected with the logic control circuit, and N linear amplification circuits connected with the N direct digital synthesis circuits in a one-to-one correspondence manner, so that N channels are formed; and the acoustic transducer array is a linear regular arrangement array and comprises N transducer array elements connected with the N linear amplification circuits in a one-to-one correspondence manner, the width of each transducer array element is L, the spacing distance between the adjacent transducer array elements is dL, the resonance center frequency of each transducer array element is F, and the relative bandwidth is B. According to the invention, a good grating lobe suppression effect can be obtained with relatively low technical cost.

The present invention discloses a MIMO radar sparse array optimization method based on a sleep monitoring scenario. The sparsity of the array elements is determined in combination with the actual sleep scenario, and the two-dimensional beam angle is constrained. The full angle scan is achieved by changing the beam pointing within the constrained angle, and the highest sidelobe level value of the directional pattern under all angle pointing is obtained. The multi-objective particle swarm iterative model is used to solve the optimal array element spacing, and the excitation coefficient is solved in combination with the convex optimization algorithm, and finally the array element position and excitation coefficient matrix are obtained. Compared with the uniform array, this method reduces the number of array elements, reduces the hardware implementation cost, weight and pressure, and improves the angular resolution; compared with the traditional sparse array algorithm, this method can determine the sparsity of the array elements in combination with the actual sleep scenario, and solves the problem that when the beam pointing changes in the traditional sparse array, the directional pattern will have high sidelobes and large grating lobes, ensuring that the directional pattern under all angle pointing within the constraint range has a low sidelobe level.

The invention discloses an antenna unit capable of being used for a low RCS array, and belongs to the technical field of antennas. The antenna comprises a radiation structure layer and a feed network layer. The radiation structure layer comprises rectangular metal patches and special-shaped metal patches which are arranged in an array. The rectangular metal patches form a 2 * 4 array in the same plane; the number of the special-shaped metal patches is two, and the two special-shaped metal patches are located below the 2 * 4 array. The feed network layer is located below the radiation structure layer, and a T-shaped branch knot is arranged between an upper metal plate and a lower metal plate of the feed network layer; a radio frequency socket is arranged at the bottom of the lower metal floor, and an outer conductor of the radio frequency socket is connected with the lower metal plate; an inner conductor of the radio frequency socket penetrates through the lower metal floor and is connected with a common end of the T-shaped branch knot, and two branch ends of the T-shaped branch knot are connected with the corresponding special-shaped metal sheets through the corresponding feed probes. According to the invention, a radiation function and a scattering control function are integrated, so that the radiation performance of the antenna is ensured, and the RCS of the unit and the scattering grating lobes during array splicing use are obviously reduced.

The present invention discloses a joint multi-beam angle radar high-resolution imaging method based on the least squares method. By establishing a complete signal model, this method incorporates the sidelobe and grating lobe signals of the transmitted beam into the imaging process, avoiding treating them as interference but rather as an effective supplement to the reflected information of the target direction. The present invention proposes a joint estimation method based on the least squares method, which significantly reduces sidelobe artifacts, improves angular resolution, and alleviates the interference problem of grating lobes in sparse arrays by performing overall optimization processing on the echo signals of multiple transmitted beam angles. This method can effectively improve the imaging resolution of millimeter-wave radar in complex scenarios and has broad practical application potential.

The application discloses a STCA-MIMO radar anti-interference method based on nonlinear time delay, which comprises the following steps: calculating target echo signals based on nonlinear time delay of transmitting array elements; carrying out digital mixing and matching filtering on the target echo signals to obtain preprocessed signals; determining a first transmitting steering vector and a first receiving steering vector according to the preprocessed signals; calculating a covariance matrix of STCA-MIMO radar system receiving data; calculating an adaptive weight vector by using a robust direct data domain beam forming technology based on the covariance matrix and an actual receiving-transmitting joint steering vector of a target; calculating a first receiving-transmitting joint steering vector of the STCA-MIMO radar system; and carrying out beam forming by using the first receiving-transmitting joint steering vector and the adaptive weight vector. The application can effectively suppress interference signals in the main lobe of the STCA-MIMO radar, and solves the problem of the decline of interference suppression performance in the prior art when the interference is located near the distance grating lobe of the main lobe of the real target.

The present invention discloses a large-field-of-view scanning method for a laser radar based on a liquid crystal phased array, comprising the following steps: expanding and deflecting a laser light source according to the aperture size of the liquid crystal phased array to obtain a target beam; phase-modulating the target beam using the liquid crystal phased array to achieve beam deflection, continuously changing the applied phase modulation to achieve annular scanning of the beam; reflecting the annular scanning beam using a conical reflector to achieve spatial transformation, thereby converting the circular scan into an arcuate scan and obtaining a preliminary large-field-of-view arcuate scan; reasonably setting the parameters of the conical reflector and the distance between the conical reflector and the liquid crystal phased array to filter out stray light such as grating lobes outside the scanning beam, thereby obtaining a final large-field-of-view arcuate scan. The present invention improves the scanning field of view of a phased array laser radar, filters out stray light such as grating lobes outside the scanning beam, and obtains high-quality large-field-of-view arcuate scans.

The utility model discloses a mining directional antenna, which comprises a reflecting plate, a radiating unit, a forming power division network plate, a feed network cable and a radio frequency connector, the radiating unit and the forming power division network plate are both mounted on a first mounting surface of the reflecting plate, and the radio frequency connector is mounted on a second mounting surface of the reflecting plate. The radiation unit comprises a plurality of radiation subunits, the feed network cable comprises a first feed network cable and a second feed network cable, the plurality of radiation subunits are in coupling connection with the forming power division network board through the first feed network cable, and the forming power division network board is in coupling connection with the radio frequency connector through the second feed network cable; wherein the radio frequency band of each radiation subunit is from 1710 MHz to 2700 MHz, and the radio frequency connector is set as an external port. The antenna is high in transmission efficiency, stable in signal receiving and transmitting, high in sensitivity, low in antenna grating lobe and high in multipath interference resistance.

The application discloses a kind of based on rectangular waveguide lens terahertz two-dimensional multi-beam antenna, including two-dimensional feed array, rectangular metal cavity and rectangular waveguide lens;Two-dimensional feed array includes first metal substrate, first metal substrate is provided with several rectangular waveguide feed units, each rectangular waveguide feed unit is connected with feed port;Rectangular waveguide lens includes second metal substrate, second metal substrate is provided with several rectangular waveguide phase shift units, and the rectangular waveguide phase shift units of adjacent row are mutually staggered distribution.The application is realized two-dimensional multi-beam scanning by the way of two-dimensional feed array bias feed, with the advantages of two-dimensional scanning angle and gain can be arbitrarily designed, large bandwidth advantage.The application adopts rectangular waveguide array to form metal lens, with the advantages of low high-frequency loss, small size;At the same time, through waveguide array staggered and period compression, mirror image grating lobe is eliminated, with the advantages of low grating lobe, large scanning angle.

The invention discloses a tightly-coupled ultra-wideband dual-polarized antenna, and belongs to the technical field of antennas. The antenna is composed of a plurality of antenna units which are arranged in a two-dimensional period. The antenna unit comprises a wide-angle medium matching layer, an antenna radiation layer, a first supporting layer, a resistance type frequency selection surface layer, a second supporting layer and a metal floor layer which are sequentially arranged from top to bottom, and further comprises two feed baluns which are vertically arranged. Wherein the antenna radiation layer adopts an interdigital tight coupling dual-polarization dipole as a radiator. By introducing composite structures such as the wide-angle dielectric matching layer, the interdigital tight coupling dipole and the resistive frequency selective surface, the characteristics of ultra wide band, low profile and high gain are realized at the same time, the impedance matching performance of the antenna under a wide scanning angle is optimized, and the edge truncation effect and the grating lobe problem are effectively inhibited.

The application provides a metasurface array, which is composed of several metasurface subarrays of different shapes; the metasurface subarrays cannot coincide with the original metasurface subarrays after being rotated by 90°, or 180°, or 270°, or being mirror flipped, the application adopts irregular subarray division for a super large scale reflector array, compared with a traditional structure without subarrays, the number of bias lines is greatly reduced, that is, the number of control interfaces of the smart reflector is reduced, under the condition that the performance indicators such as scattering pattern gain and sidelobe are slightly reduced; compared with regular subarray division, the grating lobe level can be obviously suppressed due to breaking the periodicity of the phase center of the subarray, and the application can effectively reduce the system cost, power consumption and engineering implementation difficulty.

This invention discloses a method for suppressing high sidelobes / grating lobes in a wide-area ultra-sparse MIMO radar system, comprising the following steps: (1) Based on a MIMO radar with sparse node distribution, select one set of array elements, each array element transmits orthogonal waveforms to obtain a joint transmit / receive beam pattern; (2) By changing the carrier frequency, obtain joint beam patterns respectively, multiply the obtained beam patterns to obtain an optimized joint beam pattern; (3) Select another set of array elements, repeat steps (1) and (2) to obtain joint beam pattern results under different array configurations; (4) Multiply the joint beam patterns under all array configurations to obtain the final optimized joint beam pattern. By multiplying the carrier agility results of the joint transmit / receive beam patterns obtained from different carrier frequencies of different MIMO radar transmit / receive array configurations, the joint transmit / receive beam pattern optimization is achieved, resulting in a joint transmit / receive beam pattern with lower sidelobes.

The invention discloses a loudspeaker array beam forming method, electronic equipment and a storage medium, and relates to the technical field of beam forming, and the method comprises the steps: obtaining a distance value between each loudspeaker unit in a loudspeaker array and a corresponding impedance boundary, and an impedance value of the impedance boundary; matching a target beam forming filter in a plurality of preset beam forming filters according to the distance value and the impedance value; and filtering the input signal of the corresponding loudspeaker unit based on each target beam forming filter to form an output beam. In practical application, the applicable beam forming filter can be quickly matched only by acquiring the specific impedance boundary parameters of the current environment, the method can adapt to the boundary environment with limited acoustic impedance characteristics, the influence of the impedance boundary on sound wave propagation is accurately reflected, the beam pointing precision and the acoustic contrast are remarkably improved, and the method is suitable for popularization and application. And the grating lobes of the dark area are reduced, so that the optimization of the beam performance is realized on the premise of not needing on-site acoustic measurement, and the universality and the accuracy are both considered.

The invention relates to the technical field of underwater acoustic detection, in particular to an acoustic monitoring system and method based on multi-frequency measurement and grating lobe rejection, and the system mainly comprises a transmitting module, a receiving array and a signal processing module. According to the invention, through fusion of multi-frequency measurement, grating lobe elimination, sparse array design and a weighted splicing algorithm, high-precision and wide-angle acoustic monitoring under the condition of less than or equal to 32 channels is realized. Meanwhile, the system has the advantages of low cost, high flexibility, strong anti-interference capability, strong real-time performance, high resolution, adaptability to complex environments and the like, and has a good engineering application prospect.

The present invention relates to a sparse array configuration and angular resolution optimization method for a 77GHz automotive radar. The sparse array is composed of multiple transmitting antennas and multiple receiving antennas; the sum of the spacings between the multiple transmitting antennas is twice the sum of the spacings between the multiple receiving antennas, and in a virtual array element formed by the multiple receiving antennas, the subarray spacing is equal to the sum of the spacings between the multiple receiving antennas; and the spacings between adjacent receiving antennas, when arranged from small to large, form a geometric progression. The present invention constructs a virtual array with equally spaced subarrays and low grating lobes by specifying the spacings between the transmitting and receiving antennas. By comparing the beamforming results of the windowed subarrays and the sparse array, the effects of sidelobes and grating lobes on the angular measurement of the 77GHz automotive radar are effectively reduced. The constructed sparse array improves the angular resolution performance of the 77GHz automotive radar, while also reducing interference from grating lobes and sidelobes, thereby improving the performance of the 77GHz automotive radar.

The invention discloses an antenna parameter design method of a synthetic aperture radiometer and the synthetic aperture radiometer, and belongs to the technical field of synthetic aperture radiometers. Wherein an antenna array in the synthetic aperture radiometer is used for uniformly sampling an observation target on a spatial frequency; each antenna in the antenna array is a sub-array antenna; the antenna parameter design method comprises the step of matching the zero point position of a sub-array antenna pattern with the grating lobe position of an array factor of an antenna array to obtain the antenna parameter of the synthetic aperture radiometer. According to the method, the number of subsequent receiving channels and correlators does not need to be increased, the sampling interval of a spatial frequency domain does not need to be changed, the spatial frequency sampling period is not shortened, meanwhile, the original signal processing flow of the aperture radiometer is not affected, and grating lobes can be suppressed on the premise that the system complexity, accuracy, angular resolution and calculation efficiency are not sacrificed.

Provided in the present application are an antenna system and a communication apparatus, which can reduce the energy of grating lobes in antenna arrays, and thus are suitable for more scenarios, and can be applied to communication scenarios. The antenna system comprises a plurality of antenna units, wherein each antenna unit comprises a first antenna and a second antenna, operating modes of the first antenna comprising a high-order mode in a first frequency band, operating modes of the second antenna comprising a fundamental mode in the first frequency band, and the first antenna and the second antenna being located in a same planar antenna array.