Design of Output-Input Inversed Polarity Pulse Power Divider for Ultra-Wideband Communications

Abstract

The implementation of a output-input inverse polarity pulse power divider based on the use of a SMA directly feed asymmetric coplanar stripline phase inverter for ultra-wideband communication is proposed. The novelty of the proposed power divider can be demonstrated that the electromagnetic energy guided by the CPW divides naturally into the slots of two asymmetric coplanar striplines and the polarity of the input pulse be reversed by asymmetric coplanar stripline to SMA transition. SMA connectors are mounted directly to the output asymmetric coplanar striplines and seven pairs of metal rods are soldered vertically to the substrate with seven resistors on top for improving the isolation and matching performance. The simulated and measured result in frequency domain agree well showing equal power division with less than 2 dB of additional insertion loss and in-phase for the outputs ports across the desired band of 0.4 GHz to 4.0 GHz (one decade) which indicates an ultra-wideband feature. The return loss for all the ports and the isolation between the two output ports are better than 10 dB which demonstrates good matching and isolation performance. To illustrate the short pulse performance of the proposed power divider, Inverse Fourier Transformation is used to calculate the input and output signals. The Gaussian pulse with a −10 dB bandwidth is utilized as the stimulus signal and the port signals in time domain are derived from the measured scattering parameters and discussed. Time domain results show that the same magnitude of the pulse is obtained between the two outputs and the polarity of the output pulse has been inversed compared to the input one. Simulated and measured results in both frequency and time domain agree well and show the feasibility and validity of the proposed power dividers.