In this paper, a new dual-band Wilkinson power divider (WPD) is designed and fabricated using novel low and high impedance stubs instead of quarter-wavelength transmission lines. The proposed circuit was analyzed using odd and even mode analysis, and the optimal values of design parameters were obtained using the particle swarm optimization algorithm. The designed power divider has input reflection coefficients (S11) of −22.1 and −17 dB at the first operating frequency of 2.2 GHz and the second operating frequency of 14.2 GHz, respectively. It also improves stop-band and fractional bandwidth (FBW) while maintaining a simple topology. The proposed WPD suppresses undesired harmonics from the second to the fifth with an attenuation level of less than −20 dB in the first band and generates a broad stop-band (4.4–11.5 GHz). In the first band, the FBW is 54.5%, and in the second band, it is 20.1%.

In this paper, a new asymmetric structure is proposed for the dual-band unequal application, in which both open- and short-ended stubs are applied. Closed-form design equations are obtained for the proposed power divider using the modified even- and odd-mode analysis method. It is observed that the proposed power divider can operate at high frequency ratio from 2.3 to 3.7 and has a wide operating band. Besides, this proposed circuit can offer flexibility in fabrication. For verification, two power dividers operate at 1/2.5 GHz with different values of line impedance are fabricated and tested. There is good agreement between simulation and experimental results, validating the proposed design concepts.

In this paper, for the first time, we present a novel Pi-shaped structure using resonators for multiband applications. The multiband Pi-shaped structure with LC resonators is analyzed. In order to demonstrate the proposed multiband Pi-shaped structure, one tri-band Wilkinson power divider and one tri-band rat-race coupler are designed, fabricated, and tested. The compactness of the two demonstrated components is well kept by putting all stubs with resonators inside the components themselves. Measured results are in good agreement with the simulated results.