Derivation of the optimum distance between periodically spaced vias for leakage suppression at S‐band

Abstract

ABSTRACTIn this letter, the optimum center‐to‐center separation between vias in the conductor‐backed coplanar waveguide (CBCPW) is presented for leakage suppression in the dielectric region. Leakage mechanism at high frequencies associated with surface wave or parallel‐plate mode were widely studied in the past. In this work, antenna arrays have been used to compare leakage in CPW and CBCPW feed network at S‐band. By using identical antenna elements, CPW‐fed slot dipole antenna array has been compared against CBCPW‐fed slot dipole antenna array with a ground via fence. Instead of using shorting pins with minimum nonzero gap, optimum center‐to‐center separation distance between vias has been derived from the bandgap phenomenon. Approximately 20% of total loss across the frequency range of interest in CPW feed network obtained from the comparison of the CPW‐fed antenna array against the CBCPW‐fed antenna array can be attributed to unwanted leakage in the dielectric substrate. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1257–1260, 2016