Multiway wideband power dividers

Abstract

In this article, we propose a new design methodology to broaden the bandwidth of a multiway Bagley power divider (BPD). Single‐frequency matching uniform quarter‐wave‐length microstrip lines in the conventional design are replaced with impedance‐varying transmission lines of broadband matching characteristics. The equivalent transmission line model is used for profiling impedance variations, which are governed by a truncated Fourier series. Such variations are determined by finding the optimum series coefficients that result in a wideband matching nature. The proposed technique leads to flexible spectrum allocation and matching level. Furthermore, the resulting structures are compact and planar. First, analytical results of three 3‐way BPDs of different fractional bandwidths are presented and discussed to validate the proposed approach. Then, two examples of 3‐ and 5‐way BPDs with bandwidths of 4–10 GHz and 5–9 GHz, respectively, are simulated, fabricated, and measured. Simulated and measured results are in a good agreement, with input port matching of below −15 dB and −12.5 dB for the 3‐ and 5‐way dividers, respectively, over the bands of interest. The obtained transmission parameters of the 3‐ and 5‐way dividers are −4.77 ± 1 dB and −7 ± 1 dB, respectively, over the design bands. The proposed wideband dividers find many applications in microwave front‐end circuitry, especially in only‐transmitting antenna subsystems, such as broad‐ and multicast communication links. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:730–738, 2015.