Very Compact Reconfigurable Planar Filter With Wide-stopband Performance for Sub-6 GHz 5G Systems

摘要

This manuscript introduces a new and very compact planer reconfigurable bandpass to band-pass/low-pass filter covering the 0 to 1 GHz and 3.4 to 3.8 GHz bandwidth for the fifth-generation (5G) systems. The patch filter uses three trisection resonators with $50 Omega$ transmission lines for input and output feedings. To realize high selectivity, finite transmission zeros have been successfully realized on the upper and lower sides of the in-band transmission. By employing another resonator between the input and output transmission line feedings, lowpass performance and reconfigurability characteristics are obtained. The cross-coupling factors between the adjacent and non-adjacent resonator lines are optimized to achieve the required performance. The presented filter is analyzed and optimized with the aid of the computer simulation technology (CST) simulator, and is implemented and printed on a Rogers RO3010 dielectric material with a relative permittivity of 10.2 and loss tangent of 0.002. Also, the filter has a very compact size of $10 imes 8 imes 1.27$ mm³. Good agreement is obtained between the simulation and measurement characteristics.