Miniaturized varactor-tuned hairpin bandpass filter with single bias

This paper presents a miniaturized varactor-tuned hairpin bandpass filter that operates with a single bias supply. The demonstrated filter consists of hairpin resonators, varactors, and bias capacitors. The filter is designed using a bandwidth- compensated miniaturization technique, resulting in a compact 50 mm times 26 mm sized filter. With a single bias supply ranging from 2 to 4 V, the center frequency of the filter can be adjusted between 800 MHz and 1 GHz while maintaining a low insertion loss in the passband.