| The millimeter-wave(mm Wave)band with the high available spectrum is widely used in communication,radar,and detection.Especially the mm Wave phased array antenna,with its characteristic of changing the beam direction or shape in real-time,can fulfill the need of wireless systems,including large bandwidth,anti-interference,and enhanced coverage.However,the traditional mm Wave phased array antenna has a limitation: a limited scanning angle or severe gain drop when scanning at a large angle.Therefore,three different wide-angle scanning phased array antennas are designed to address this problem in this essay thesis.In particular,the idea of a phased array antenna based on the heterogeneity of the array element beam is proposed.Moreover,two mm Wave wide-angle scanning phased array antennas are designed according to this idea.The specific research is as follows:1.Wideband and wide-angle mm Wave scanning phased array antenna based on metasurface: An aperiodic metasurface is used to control the aperture field distribution as well as improve the impedance matching under low profile,ensuring a subarray can achieve broadband.Based on this subarray,a 4×4-element planar phased array antenna with 1-D scanning capability is designed.A (?)-shaped structure is also introduced between each two subarrays to reduce the uniformity of the aperture field on the array surface,thereby increasing the 3-d B beamwidth along the scanning direction and achieving a wider scanning range.The simulation results show that in the 5G mm Wave frequency band(24.25-29.5GHz),the phased array antenna’s 3-d B gain variation scanning range can be greater than ±55° with a maximum of ±60°.The measured results are in good agreement with the simulation.2.Millimeter-wave phased array antenna based on beam heterogeneity and elongated planar aperture array elements: The idea of phased array antenna based on array element beam heterogeneity is proposed to improve the scanning capacity of phased array antennas.The limitation of the scanning range of traditional phased array antennas has been broken due to the design freedom provided by the diversity of the array element pattern.According to that,firstly,an elongated planar aperture antenna array element is designed.By stretching the aperture along one dimension,the array element achieves stable and high gain in the broadband.Then,the array element is adjusted by introducing structural asymmetry,achieving the beam inclination.On this basis,the elongated planar aperture antenna array elements with different beam inclinations are used to replace the traditional subarrays,forming a 1×4 element wide-angle scanning phased array antenna.The measurement results show that in the 5G mm Wave frequency band(24.25-29.5GHz),the phased array antenna’s 3-d B gain variation scanning range can be greater than ±62° with a maximum of ±68°.3.Millimeter-wave phased array antenna based on beam heterogeneous PIFA elements: To further improve the scanning performance,the phased array antenna based on PIFA elements is proposed.First,a beam heterogeneous adjustable PIFA antenna element is designed,whose 3-d B beamwidth is greater than 125°,and the beam direction can be controlled by changing the ground size.Based on that,a 4×4-element wide-angle scanning phased array antenna is constructed.The array adopts a symmetrical feeding method to ensure the symmetry of both the structure and excitation so that the scanning performance in the opposite direction is identical.The simulation results show that in the 5G mm Wave frequency band(24.25-29.25GHz),the phased array antenna’s 3-d B gain variation scanning range can be greater than±65° and can reach a maximum of ±70°.The measured results are in good agreement with the simulation. |
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