Study And Application Of Wideband Waveguide Phase Shifter

With the rapid development of the microwave and millimeter-wave technology, phase shifter is a kind of microwave control circuit whose function is to control the phase of the microwave signal. It has a broad application prospects in microwave communication and Phased-Array Radar. Phase shifter is one of the key components in Phased-Array Radar. Its performance has direct effect on phased-array radar system. Waveguide phase shifter is worthy of important research value due to its high frequency, high power capacity, low insertion loss, wide bandwidth, and low cost. This paper mainly studied the Ka-band waveguide phase shifter and its application in power divider with equal phase.The background and development of phase shifter are simply discussed, the principle of work and characteristic is explained then, and the basic theory of several common phase shifter such as mechanical phase shifter, semiconductor phase shifter, ferrite phase shifter are introduced. Although the structure of these phase shifters are compact and it presents high accuracy differential phase shifter, the bandwidth is narrow and it has high insertion loss. This article mentions a new way by adding metal column to stepped waveguide compared to waveguide which has the same length to design the Ka-band phase shifter. The waveguide phase shifter realized the 90 degree differential phase shifter in a short length with full bandwidth at 26.3-40 GHz. It is worth of important advantage is high frequency, high power capacity, low insertion loss. Also the structure is in a plane, easing for processing. After test, the return coefficient is better than-20 dB, the phase difference of two output is 90 ?5, and the isolation is better than 0.45 dB at Ka-band.Then a compact Ka-band waveguide 3-db hybrid with full bandwidth is proposed in this paper. The full bandwidth is achieved by introducing multistep-matching network of waveguide and adding alterable specification metal inserts based on the innovation of famous Riblet-coupler. The structure is simply, and the hybrid is assumed symmetric both longitudinally and transversely. The measured results show that the power-split unbalance within 3±0.7 dB; return coefficient is better than-18 dB and isolation of the bridge can achieve 20 dB, respectively, phase difference of the two output terminals within 90 ?3 are achieved over the full Ka-band waveguide bandwidth.Last we connect the phase shifter with 3-dB hybrid to a powder divider with equal phase. The test results show that at the frequency of 26.3-40 GHz, the return loss is better than-20 dB, and the isolation is higher than 19 dB, and the phase difference is unbalance within 0-4 and 0 +7.