Balanced Wideband Impedance Transformer (BWIT) for Common-Mode Resonance Cancellation in UWB Dipoles over a Ground Plane

Within the context of modern radios, differential Radio Frequency (RF) front-ends provide much greater immunity to noise and distortion by suppressing second order harmonics. Recent advancements in differential RF front-ends offer high dynamic range, high linearity, and low noise in the transceiver chain. However, a major bottleneck with differential systems is the presence of common-mode resonances when scanning to low angles across large bandwidths. In this paper, we present a novel wideband differential feed for ultra-wideband (UWB) dipoles like the Tightly Coupled Dipole Array (TCDA). Our Balanced Wideband Impedance Transformer (BWIT) feed is developed for the UHF-S band (viz. 0.4 GHz to 3.2 GHz) with emphasis on resonance-free wide-angle scanning in the E-plane.