A new kind of millimeter wave equalizer based on microstrip pin resonator

Equalizers are widely used to compensate for inconsistencies in TWTA´s gain response. Coaxial equalizer and microstrip equalizer are two of the most common kinds. They have good performances bellow X wave band But when they are used in millimeter wave band, they have some disadvantages. For coaxial millimeter wave equalizer, More than one resonating frequencies will be generated by one resonator. This is mainly attributed to the discontinuities of the structure. Microstrip millimeter wave equalizer has no such problems. But it has high insertion loss and low Q factor. This paper first analyzed the disadvantages of the coaxial and microstrip equalizers and then provided a new structure of millimeter wave equalizer called microstrip pin equalizer. By placing microstrip resonators on the waveguide transmission line just like a pin, this equalizer can obtain good performance in millimeter wave band. Calculation for this resonator is offered. The High Frequency Structure simulator (HFSS) is used to simulate this model. All results show this equalizer has a great improve in insertion loss and Q factor, and has no additional resonating frequencies. What´s more important, it is very convenient to adjust the curve. By changing the length of resonator and the value of resistor, the resonator can be frequency and attenuation adjustable. At last, a millimeter wave equalizer composed of these resonators was designed.