Hybrid lumped/distributed band-pass filter in IPD technology for ultra-wideband applications

This paper deals with the design of a fourth-order UWB (low frequency band) filter dedicated to the range 3.1 - 4.175 GHz. The topology under study is based on that of a hybrid band-pass filter with lumped components and distributed lines within a thin film made in IPD technology to meet the requirements of strong miniaturization. Moreover, the filter sensitivity and its fabrication cost had both to be low. To enhance the rejection at high frequencies, where the UWB electrical specifications are very drastic, the topology proposed here is that of a DBR filter with two coupled distributed lines. After its description, its sensitivity is analyzed to validate the topology. The experimental data produced by this filter designed in IPD technology are presented and discussed.