Self-Packaged Ultra-Wideband Balanced Bandpass Filter Using Multilayer Liquid Crystal Polymer Circuit Technology

An ultra-wideband balanced bandpass filter (BPF) by using multilayer liquid crystal polymer (LCP) circuit technology with self-packaging feature is presented in this paper. The differential-mode (DM) half circuit of the proposed filter is provided and analyzed, showing that the balanced filter exhibits a four-pole ultra-wideband Chebyshev filtering response. In addition, the common-mode (CM) signals can be suppressed in a wide bandwidth region owing to the all-stop coupled-line topology in the CM equivalent circuit. Finally, an LCP balanced BPF with ultra-wideband Chebyshev response is designed, fabricated and measured. Simulated and measured results are recorded in good agreement, well validating the design method.