Compact Low-pass Filtering-response Wilkinson Power Divider with Wide Harmonic Suppression

Abstract

In this article, a compact Wilkinson filtering power divider (FPD) operating at a frequency of 2.25 GHz with low-pass behaviour and a wide attenuation band is presented for LTE communications. The microstrip structure is modelled by using T - shaped stub resonators loaded symmetrically in the microstrip line to achieve a low-pass filtering response. The lowpass filter operates at a 2.4 GHz cut-off frequency with 0.35 dB insertion loss, and 62 dB/GHz roll-off factor (ROF). Two defected ground structures (DGS) of dissimilar shapes are incorporated in the ground plane to attain wide attenuation band performances up to 14.6 GHz with an attenuation level of -20 dB, and a relative stopband rejection of almost 144 %. Equal power division is attained by embedding the stub-loaded microstrip structure in the traditional circular-shaped Wilkinson power divider (WPD). Good isolation can be obtained by connecting a 100 Ω isolation resistor (IR) amid the two output ports. For experimental validation, the lowpass filter and FPD designs are fabricated and measured.