Small Sized Double-fold Hairpin Line Microstrip Bandpass Filter at 2400 Mhz for Rf/ Wireless Communications

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. This paper presents a new class of folded hairpin line microstrip resonator filters with 40-50% reduction in size compared to the conventional hairpin line resonators. The proposed double-fold hairpin line microstrip filters are slow wave open loop type narrow band, high selectivity, small sized and low cost band pass filters for wireless/RF trans/receive communication systems for ground and space applications in S-band. In the proposed filter 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 filter having the double-folded hairpin line resonators. The measured results are close to the simulated results, with great reduction in size compared to the conventional planar hairpin line structure. KEYWORDS---Double-fold hairpin line resonator, slow-wave open–loop resonator, miniaturized hairpin line, coupling coefficients, ADS software, computed response.