A new method for designing compact Wilkinson power dividers with three order harmonics suppression is presented. The quarter-wavelength transmission line in the traditional Wilkinson power divider is replaced by two pairs of parallel coupled lines with one end connected in series with an open stub. With this structure, the quarter-wavelength line will be shorter and three attenuation poles can be added in the stopband. As a result, this newly proposed structure carries the functions of impedance matching at operating frequency and three orders harmonics suppression. In this study, an example of power divider operating at 1 GHz is designed and fabricated. The measured results show good performance at the operating frequency. In addition, the second, third and fourth harmonics suppressions are 43 dB, 49 dB and 37 dB, respectively, which validates the feasibility of the proposed design.
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