Ultra-compact UHF Band-pass Filter Designed by Archimedes Spiral Capacitor and Shorted-loaded Stubs

Abstract

UHF microstrip band-pass filters (BPFs) that much smaller than the referred BPFs are proposed in this communication. For the designing purpose of compactness, archimedes spiral capacitor and ground-loaded stubs are utilized to enhance capacitances and inductance of a filter. Two compact BPFs denoted as BPF 1 and BPF 2 are designed by applying these techniques. The size of BPF 1 and BPF 2 are 0.062 λ g × 0.056 λ g and 0.047 λ g × 0.043 λ g , respectively, where λ g are guided wavelengths of the centre frequencies of the corresponding filters. The proposed filters were constructed and measured, and the measured results are in good agreement with the simulated ones.

Ultra-Compact Band-Pass Filter at Low Frequency of Operation

“…In [11], a parallel coupled microstrip hairpin based band-pass filter is presented with a large filter dimension. In [12], spiral capacitors with vias are used to design a band-pass filter in MHz frequency band.…”