Self‐packaged MISL‐based miniaturized high Q factor bandpass filter

Abstract

This paper proposes a technique named self‐packaged metal integrated suspended line (MISL) to design a high Q factor bandpass filter (BPF). This unique construction simplifies the traditional suspended stripline and substrate integrated suspended line configuration and creates a loss‐reduced structure, allowing for the implementation of high Q‐factor circuits. To demonstrate the advantages of the MISL platform, the shorted 3D metal stepped impedance resonators are first investigated using a miniaturized prototype based on this novel platform. Subsequently, a third‐order BPF based on MISL technology is designed, fabricated, and characterized. The fabricated BPF exhibits a minimum insertion loss (IL) of 0.31 dB, with centre frequencies of 5.88 GHz and 3‐dB fractional bandwidths of 19.8%, respectively.