Design of a silicon-based wideband bandpass filter using aggressive space mapping

Abstract

The auxiliary diagnosis and debugging of filters play an increasingly important role in the design of microwave filters. In particular, aggressive space mapping (ASM) is one of the most commonly used debugging methods. This paper introduces ASM and designs a seventh-order microstrip interdigital filter with a center frequency of 24 GHz and a fractional bandwidth of 25% with ASM. The filter reached design indexes after four iterations, which greatly reduces the number of simulations in fine model, thereby saving time. It was fabricated on high resistance silicon substrate and the size of the chip is 6.8 mm×2.4 mm×0.4 mm. The measurement results show that the fabricated filter has a center frequency of 24 GHz, a fractional bandwidth of 24.17%, an insertion loss of 1.95 dB, a return loss of 12 dB, and an out-of-band rejection of 40 dB.