An Ultra-Compact Hairpin Band Pass Filter With Additional Zero Points

A novel quasi-hairpin filter is presented in this letter. The filter shows ultra-compact size, steep selectivity, and deep stopband rejection with additional transmission zero points. The fourth-order filter operating at 1.69GHz with a fractional bandwidth of 10% occupies the active area of 5.5mmtimes6.2mm (0.031lambda
₀
times0.035lambda
₀
)