On-chip single-to-balanced bandpass filters with wide upper stopband

Summary form only given, as follows. On-chip single-to-balanced bandpass filters with wide upper stopband are proposed. They are based on a simple multicoupled line structure along with loaded capacitors. The use of inductor is avoided so as to achieve very compact size when implemented on chip. Specifically, two single-to-balanced filters of 2nd- and 3rd-order bandpass response are demonstrated using the GaAs pHEMT process. Their chip sizes are 1mm×1mm and 1.5mm×1mm for a center frequency of 5.5 GHz and a bandwidth of about 18%.