Reduced size dual band pass filters for RFID applications with excellent bandpass/bandstop characteristics

Abstract

This paper presents the design of two reduced size dual-band metamaterial bandpass filters and its simulation followed by measurements of proposed filters. These filters are supporting different frequency bands and primarily could be utilize in radio frequency identification (RFID) application. The filter includes three cells in which two are symmetrical and both inductively coupled with the third cell which is present in between them. In the proposed designs, three different metamaterial composite right/left handed (CRLH) cell resonators have been analysed for compactness. The CRLH cell consists of an interdigital capacitor, a stub/meander line/spiral inductor and a via to connect the top of the structure and ground plane. Finally, the proposed dual band bandpass filters (using meander line and spiral inductor) are showing size reduction by 65% and 50% (with 25% operating frequency reduction), respectively, in comparison with reference filter using stub inductor. More than 30 dB attenuation has been achieved between the two passbands.

A compact reconfigurable bandpass/lowpass filter with independent transmission zeros based on generalized NRI metamaterial

“…Filters based on NRI‐MTM offer unusual properties such as NRI, zero propagation constant, and antiparallel phase and group velocities . Single/multipole MTM‐based bandpass filters have been designed using via and different capacitive and inductive loads . Using coupled CRLH transmission line (TL), very sharp filters and wide band bandpass filter with TZs were proposed.…”

A Double Optimized Transmission Zeros Based on Pi-CRLH Dual-Band Bandpass Filter

“…Similarly, coupled mechanism bandpass filters can lead to a small size and sharp CRLH filters [11][12][13]. Different methods of compact and sharp multi-band CRLH filters are also proposed [14][15][16][17][18][19][20][21][22][23].…”

Dual band pass filter with sharp transmission zeros for wireless applications

“…Dual-band filters are commonly used as multiband filters in different wireless applications and have been extensively analyzed and reported in many articles. Various techniques such as step-impedance technique [6][7][8], stub loaded technique [4,[9][10][11][12], source load cross-coupling technique [13,14], Electromagnetic band gap [15], artificial metamaterial transmission lines [16,17] and capacitive load technique [18,19] have been applied to design the proposed resonators for achieving multiband behavior. The step-impedance resonator (SIR) can achieve dual band behavior by adjusting the impedance ratio and the electric-length of the resonators.…”