Study Of The Broadband And High Gain In-plane Feed Reflector Antennas

In-plane feed reflector antenna is a new type of metasurface antenna based on phase gradient metasurface(PGM)to solve the problem that the traditional reflector antenna's high-profile structure is not conducive to its integration and miniaturization.Compared with traditional reflector antennas,in-plane feed reflector antenna has a very low profile.So it is very suitable for use with flat-panel circuits.Moreover,its design complexity,manufacturing difficulty and implementation cost are much lower than traditional reflector antennas.Therefore,studying the in-plane feed reflector antenna has important practical significance and potential application value.In this paper,on the basis of the in-plane feed reflector antenna,combined with the development needs of modern communication systems for high-performance antennas,we conducts research on its performance deficiencies,such as narrow bandwidth and low gain.Based on the investigation of the feed and PGM that affect the performance of the antenna,specific implementation techniques for improving the bandwidth and gain of the antenna are proposed.Combined with the current development trend of multi-functional antennas,novel in-plane feed reflector antennas with ultra-wideband dual-beam radiation characteristics and high gain were designed respectively.The innovations and main contents of this article are as follows:(1)Research on the ultra-wideband dual-beam metasurface unit radiating antenna based on the I-shaped unit.Based on the I-shaped unit with independently controlled amplitude and phase characteristics,a design method of ultra-wideband dual-beam antenna is proposed.This method intends to adopt I-shaped unit to design PGM with surface wave coupling in an ultra-wide frequency band,and realize dual beams by reasonably arranging PGMs.In order to excite the metasurface unit,a quasi parallel plate waveguide is designed as a feed source.In order to verify the feasibility of the above method,the antenna model was processed and tested.The test results show that the antenna has obvious symmetric dual beam characteristics in the 8-11 GHz band,that is,it has a relative bandwidth of31.6% at the center frequency point of 9.5GHz.The peak realized gain of the antenna can reach 16.2dBi and the gain change does not exceed 5dB.The experimental test results are consistent with the simulation results,which proves the reliability of the design method.(2)Research on high-gain metasurface element antennas fed by the guided vibrator antenna array.In order to solve the problem that the low-efficiency feed of the in-plane feed reflector antenna causes the antenna gain to be low,we designed a directional vibrator structure with high-efficiency feed based on the flat-plate endfire antenna structure.The directional vibrator structure uses multiple directional vibrators to guide the propagation of electromagnetic waves,and gradually excites PGMs symmetrically placed on both sides of the vibrator,and the metasurface unit acts as an antenna elements to radiate.In order to verify the feasibility of the design,CST simulation calculations were performed on the above structure.The results show that the antenna has a maximum realzed gain of 14.8dBi in the frequency range of 2.8GHz-3.0GHz,compared with the original design,the gain is increased by 6.5dBi at 2.9GHz.The simulation results show that the antenna gain is significantly improved after improving the feed design.