The High Scanning-rate Frequency-scanning Leaky-wave Antena Design

Antenna plays an important role in wireless communication system and it plays an important tool for receiving and sending information in wireless communication system.In practical applications,such as car collision radar,satellite detection and microwave millimeter wave imaging system,the leaky wave antenna has the advantages of low profile,small volume,light weight and frequency scanning characteristics.It is especially suitable for most applications,and uses a very wide range of frequency sweep antennas.With the rapid development of wireless communications,people have more detailed performance requirements for the antenna.The previous antenna design has not been able to meet the rapid development of modern communication systems.The design of high scan rate leaky wave antennas is a new challenge to the field of leaky wave antennas in the new era.In this paper,the leaky wave radiation mechanism and frequency scanning principle of leaky wave antenna are reviewed,and the influence of group delay on the scanning rate of leaky wave antenna is theoretically analyzed.In the design of the periodic microstrip leaky wave antenna,the open stopband phenomenon is analyzed and the influence of the open stopband on the radiation characteristics of the antenna is eliminated by using the parallel short intercept and the series 1/4 wavelength impedance converter.And the antenna is optimized and improved.In order to improve the group delay response of the antenna,the two species time delay structure,the C-section coupling delay line and the complementary slot microstrip line,are designed in this paper.These two structures have all pass filtering properties in the working bandwidth,and can realize the adjustment of the peak group delay and the corresponding resonant frequency on the premise of maintaining a flat amplitude response.Rate point.Finally,based on the periodic microstrip leaky wave antenna and group delay structure,two new high scan rate leaky wave antennas are proposed,and the electromagnetic simulation software is used to test and verify the antenna.The high scanning rate antenna based on the C-section coupling delay line is 5.1GHz to 5.5GHz,its reflection coefficient and transmission coefficient are below-10 dB,the corresponding beam scanning angle range from 16 to 42 degree,the total scanning angle of 26,and the scanning rate of 65 degree /GHz,is 62.5% compared with the traditional SFP antenna,based on the complementary opening.The fully symmetric leaky wave antenna of the slot microstrip line works from 4.4GHz to 5.2GHz.The scanning angle range is 40 degrees to-36 degrees,the total scanning angle is 76 degrees,the scanning rate is 95 /GHz,the scanning rate is up to 32.6%,and the antenna can be scanned before and after the quadrant.The two antennas achieve high scan frequency scanning.