A wide stopband low-pass Wilkinson power divider

The conventional Wilkinson power divider has spurious passbands at odd multiples of the center frequency, due to the use of quarter-wave transformers. For practical applications, the spurious passbands generally need to be suppressed by cascading filters, which acts against the trend of microwave systems that are toward miniaturization and integration. In this paper, a low-pass Wilkinson power divider is designed based on artificial low-pass transmission lines. The power divider is a compact design that fits into a circuit size of 0.17λg x 0.1λg on an RO4003 substrate, where λg is the guided wavelength at the center frequency of 0.9 GHz. The low-pass power divider has well-defined passband, transition, and stopband regions. It behaves like the conventional Wilkinson power divider in the passband, while has a wide stopband from 1.8 GHz to 20 GHz, as indicated by the experimental results.