Research Of Quasi-Planar Waveguide Magic-T

Waveguide magic-Ts can be used as a power divider, comparator, and can be used in phase shifter, tuner, waveguide switches, high-power circulator. It is an important passive component of the microwave system. It plays an important role in the microwave communication system. The traditional waveguide magic-T with matching element is a branch of the three-dimensional structure and it is large. This kind of structure is not conducive to planar integration, at the same time its processing is more troublesome. So, the waveguide magic-T’ planarization, miniaturization has become an important topic. At the same time, the rapid development of wireless communication makes greater demands on microwave component, both in military field and civilian field. Therefore, on the premise of planarization, miniaturization, designing of the waveguide magic-T with wide-band, good matching, high isolation and compact structure is an important part of the research of this paper.First of all, this article simply introduces the basic purpose of the waveguide magic T, and sums up the contribution what the predecessors do on bandwidth,miniaturization,planarization of waveguide magic-T.Then, this paper analyzes the basic characteristics of four port network and theoretical knowledge of the waveguide E-T branch, waveguide H-T branch and waveguide magic-T.Then, Four kinds of quasi-planar waveguide magic T were introduced in this article.They have advantages and disadvantages and can be applied to different occasions.H-plane fork-shaped quasi-planar waveguide magic-T fit for high isolation power divider. Its working frequency band is 6.5-10 GHz, and return loss of each port is more than 20 dB, and the isolation of two output port is more than 25 dB. However, this structure is relatively complicated and large. E-plane cross-shaped quasi-planar waveguide magic-T’s working frequency band is 6.57-10 GHz and return loss of each port is more than 20 dB, and two output port isolation is more than 20 dB. Its structure is compact. It can be used as the in-phase power dividers, anti-phase power dividers,comparator. E-plane fork-shaped quasi-planar waveguide magic-T’s working band is6.57-10 GHz. When used as a power divider, the return loss of input port is more than20 dB, and two output port isolation is more than 18 dB. If it is connected with thetransition structure, the performance will be further improved. Because of its output-port is located in the model on the same side, it is easy to be installed. Improved E-plane fork-shaped quasi-planar waveguide magic-T is the most compact. Its working frequency band is 7 to 10 GHz, and its bandwidth is the most narrow among the three kinds of magic-T. Its performance is a bit poorer than other three kinds of magic-T.When used as the same phase power dividers, the return loss of input port is more than20 dB, and two output port isolation is more than 19.5 dB.Finally, we process and test the E plane cross quasi plane waveguide magic-T, and compare the test results and simulation results.