Planar Stripline Sir Bandpass Filter Development

The purpose of the article researches on the characteristic on Stepped Impedance Resonator (SIR) and sums up the Radio Frequency design method adopting SIR. The main jobs in the paper generalized followed on:1 Analyze the synthetical procedure of passive network, systematically describes basic concepts and theories that form the foundation for design of general microwave filters. The topics will cover filter transfer function, low-pass prototype filters, frequency transformations, immittance inverters and the pass-band insertion loss under the influence of the dissipation of filter elements.2 The tapped-line I/O block is systematically analyzed. Two methods of analysis and design programs of filters are given. Introduces the basic structure and characteristic of SIR.3 Generalizes the Filter design method with SIR structure adopting quarter.lambda model, and a SIR LC inter-coupling Filter with Tapped Line has been designed. Also the I/O approach was ameliorated. As we test the filter, the center frequency appeared no excursion, the bandwidth, the insert-loss, and the attenuation were accorded with the target. The deficiency lied in that the return loss was bad, and about 5dB worse than the result of simulation. Moreover, the dimension was shorted by nearly 50% if it was contrasted with the filter designed with UIR. The second passband lied in 6.7 frequency instead of thrice frequency. So the stopband was widened largely.4 Base on the design of interdigital line filters with tapped-line, rectangle bar SIR interdigital line filter was designed. As tested, the center frequency appeared no excursion, the bandwidth, the insert-loss, and the attenuation were accorded with the target. The return loss was about 4dB worse than the result of simulation. Moreover, the dimension was shorted by nearly 30% if it was contrasted with the filter designed with UIR. The second passband lied in 4.2 frequency instead of thrice frequency.