In this paper, a circuit topology of the wideband power divider is proposed based on the coupled transmission lines and complex isolation impedance. It is analyzed by the even-/odd-mode method, and the design procedure is given. Then, stripline is applied to design the proposed wideband 1-to-2 power divider, and three such power dividers are integrated for the 1-to-4 power divider network. In addition, input/output transitions and surface mounted coaxial connectors are included in such power divider network for the X-band active electronically scanned array vertical integration. Finally, multi-layer printed circuit board process is used to fabricate four channels for four such wideband power divider networks. The measurements show its operating frequencies range from 8.0 GHz to 12.0 GHz, which covers the whole X-band. The measured average insertion losses are around 2 dB. Within the X-band, the measured return losses are larger than 9 dB. The measured isolation levels within the most frequencies of the X-band are about 20 dB.

In this paper, two types of balanced-to-unbalanced quadrature couplers with six hybrid ports and arbitrary power division ratio are proposed. For Type 1, the quadrature coupler can realize two power division functions, including balanced/unbalanced to balanced-unbalanced-hybrid, and for Type 2, the quadrature coupler contains balanced -to-unbalanced and unbalanced-to-balanced power division functions. To reduce the circuit size, double-sided parallel-strip line (DSPSL) swap structure is used to replace the half-wavelength transmission line, and compact circuit size can be easily achieved. To validate the performance of the quadrature couplers, two types of the balanced-to-unbalanced quadrature couplers centered at 1 GHz with power division ratios 1:1 and 3:1 are fabricated and measured, respectively. The common mode suppression higher than 10 dB (bandwidths over than 176%) can be realized, the isolation and in-band matching level can be also improved.