A compact triple band metamaterial inspired bandpass filter using inverted S-shape resonator

Abstract

This paper presents the compact metamaterial inspired triple-band filter using two inverted S-shape resonators and two C-shape stubs with via. The proposed filter is printed on FR-4 epoxy glass substrate with 1.6 mm thickness. The 3-dB measured fractional bandwidths are 40% (1.6-2.4 GHz), 16.5% (3.9-4.6 GHz) and 14.3% (5.2-6.0 GHz) at center frequencies 2.0 GHz, 4.25 GHz and 5.6 GHz, respectively. This filter offers electrical circuit size of 0.22λg × 0.16λg where given λg is the guided wavelength at center frequency of the first passband 2.0 GHz. The performance parameter of the designed filter have been characterized by fractional bandwidth, insertion loss, dielectric constant, return loss, circuit size and group delay. Both simulated and measured results are shown to validate the proposed filter. Finally, the MTM properties of the proposed filter have been verified by extracting its dispersion diagram. It is suitable for GSM 1800, LTE 2300 and WiMAX (5.2-5.8 GHz) application.