Highly Compact, Multiband Composite-Right/Left-Handed(CRLH) Transmission Line Based Stub for GPS Applications

A highly compact, multiband composite right/left-handed (CRLH) transmission line based stub for tri-band applications with two GPS (L1, L2) frequencies, and GSM frequency, is demonstrated. The advantages of this work are as follows: 1) The three frequencies are covered by a single /4 stub, providing compactness and reducing system complexity; 2) By using a substrate with a high dielectric constant, additional size reduction is realized. The lumped element circuit model has been designed using Advanced Design Systems (ADS, Keysight Technologies Inc.) and the parameters are calculated based on the bridged-CRLH (B-CRLH) circuit model. Distributed components have been designed with a numerical simulation program, High Frequency Structure Simulator (HFSS, ANSYS Inc.). The CRLH based quarter wavelength stub is characterized by the frequency-phase dispersion diagram and scattering parameters. The demonstrated design uses a meander line structure in an M-shape, the so-called M-CRLH, to provide the shunt and series capacitance and inductance, and the bridge inductance. An open-circuited quarter wavelength (λ/4) tri-band CRLH transmission line based stub is fabricated and characterized.