A COMPACT FOURTH-ORDER MULTI-FOLD HAIRPIN LINE MICROSTRIP BANDPASS FILTER AT 1650 MHZ FOR RF/ WIRELESS COMMUNICATIONS

Jagdish Shivhare, S B Jain

Abstract: This paper describes the design, simulation/optimization and measured results of a fourth-order multi-folded hairpin line microstrip bandpass filter at 1650 MHz, with 60-65% reduction in size compared to the structure of a basic hairpin line microstrip bandpass filter. The imperical equations and relevant graphs have been used to realize adjacent and cross couplings between the four multi-folded resonators. A conventional hairpin-line resonator size is normally very large. The folded hairpin line resonator filters are compact, small sized and simple to design and fabricate. The proposed multi-folded hairpin line microstrip filter is a slow wave open loop type narrow band, high selectivity, small sized and low cost band pass filter for RF/wireless trans/receive communication systems for ground and space applications in L-band. The cross couplings have been realized between adjacent and non-adjacent resonators. The ADS-Agilent make software have been used to design and simulate the filters having the folded hairpin line resonators. The measured results are very close to the simulated results, with great reduction in size compared to the conventional planar hairpin line structure.

Keywords: Hairpin line, Centre frequency, frequency response cross couplings, Multi-fold resonator, pass-band bandwidth, attenuation band, adjacent resonators

DOI: https://doi.org/10.15623/ijret.2014.0305126