A compact Wilkinson power divider/combiner with two-section coupled lines for harmonics suppression

This paper proposes a compact Wilkinson power divider/combiner utilizing coupled lines for harmonic suppression. By replacing the quarter-wavelength transformer in a traditional Wilkinson power divider/combiner with cascading two-section coupled lines, the proposed circuit exhibits the power dividing/combing property with suppression of the second and third harmonics. Explicit design formulae and procedure are presented. The proposed power divider/combiner has been designed at 2.45 GHz and fabricated on an RO4003C substrate for verification. The measured results show 40 dB rejections at the second and third harmonic frequencies. 25 dB return loss and isolation at the operation frequency are also achieved for the implemented circuits. Except for a slight frequency shift, the measured and simulated data show a good consistency with each other.