Design of a K-band two-layer microstrip interdigital filter exploiting aggressive space mapping

The auxiliary diagnosis and debugging of filters play an increasingly important role in the design of microwave filters, where aggressive space mapping (ASM) is one of the most commonly used debugging methods. This paper introduces ASM and designs a sixth-order two-layer microstrip interdigital filter with a center frequency of 20.4 GHz and a bandwidth of 1.6 GHz using ASM. The filter reached design indexes after seven iterations, which greatly reduces the number of simulations in the fine model, thereby saving time. It was fabricated with Micro-Electro-Mechanical Systems technology and the size of the chip is 7 mm × 3 mm × 0.8 mm. The measurement result was in good agreement with the simulation result.