Ultra-Compact On-Chip Filtering Power Divider Using GaAs Technology

In this paper, an ultra-compact filtering power divider (FPD) is presented using an integrated passive device (IPD) technology on a GaAs substrate. An LC resonant block is utilized to generate a bandpass filtering response with two transmission zeros (TZs) at zero frequency and 4 GHz. A parallel LC resonator employed at the input port is used to generate another TZ at 5.8 GHz, which further enhances the upper stopband rejection. In addition, an L C impedance transformer is introduced between the L C resonant block and the parallel L C resonator to improve the matching performance. The proposed FPD is working at 2.4 GHz with a fractional bandwidth of $41.6 \%\left(\left|\mathrm{~S}_{11}\right| \lt -15 \mathrm{~dB}\right)$. The minimum insertion loss is 1.2 dB, while the upper stopband rejection achieving better than 20 dB is up to 16 GHz. The chip is ultra-compact with an overall size of only $1.4 \times 1.5 \mathrm{~mm}^{2}$.