IPD-Based Miniaturized Wideband Bandpass Filter With Frequency-Dependent Complex Source and Load

In this article, an ultraminiaturized bandpass-filtering matching network based on GaAs substrate integrated passive device (IPD) technology is proposed, which is suitable for frequency-dependent complex source and load. The presented bandpass filter (BPF) is derived from an equal-ripple Chebyshev low-pass filter prototype through frequency transformation and impedance scaling. The susceptance required by the source and load is extracted from the adjacent susceptance blocks, and the final reactance/susceptance block is equivalent to a series/parallel LC circuit at the two edge frequencies. Therefore, the proposed design has both bandpass high-selectivity and impedance matching functions, and simultaneously, the bandwidth can be flexibly controlled. Finally, a wideband BPF example with the center frequency of 3.5 GHz was simulated and fabricated with the IPD process, showing satisfactory performances.