Novel common mode suppression network for the transformation of single‐ended to balanced filters

Abstract

A novel method to obtain balanced structures is introduced. The balanced behavior of a single‐ ended structure is achieved by combining two stages of the single‐ended device, by means of a new common mode suppression network (CMSN). As an example, a conventional single‐ended balanced bandpass filter (BPF) was designed, and then transformed into a balanced bandpass filter (BBPF). Around the design frequency, the differential mode (DM) of the balanced structure inherits the performance of the single‐ended filter, whist suppressing the common mode (CM) signals more than 20 dB. Additionally, the out‐of‐band response of the single‐ended filter is improved in the balanced prototype by attenuating the first spurious frequency from 0 dB to 20 dB. Good agreement between simulated and experimental results is obtained. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2831–2833, 2016