A narrow band-pass filter type Wilkinson power divider for I-Q demodulator in microwave interferometer system

I-Q (In-phase Quadrature) demodulator is one of key components in microwave interferometer system application. Normally, I-Q demodulator consists of amplifiers, mixers, 90 degree phase shifter, power divider and band-pass filters, and it is widely used in various microwave communication systems and measurement systems. In this paper, power divider and band-pass filters are newly designed as one single passive component, therefore, I-Q demodulator topology becomes simplified. The novel narrow band-pass filter type Wilkinson power divider not only provides extremely miniaturized circuit size, but also maintains the band-pass filter performance and power division function as well. One experimental circuit shows good agreement with the theoretical simulation.