Ultra‐miniaturized filtering power divider chip on integrated passive device technology using complex isolation network

Abstract

In this letter, an ultra-miniaturized filtering power divider (FPD) chip based on integrated passive device (IPD) technology using a complex isolation network is proposed. Three lumped L represents inductor, C represents capacitor (LC) tanks and two electromagnetic hybrid coupling units are used to realize the third-order quasi-elliptical filtering response with high-frequency selectivity and wide stopband, which are designed and realized by using the IPD process to achieve ultra-miniaturized size. In addition, the complex impedance is utilized to form the isolation network, so good in-band isolation can be easily achieved. Moreover, the working principle and design method of this proposed FPD is well illustrated, a prototype with 3-dB fractional bandwidth of 19.3% at 2.6 GHz (f0) is in final designed and fabricated. The isolation is higher than 16 dB within the passband, and upper-stopband attenuation higher than 20 dB is extended to 40 GHz (15.4f0). It occupies only 2.76 mm × 2.0 mm, that 0.023λ0 × 0.017λ0, where λ0 is the free-space wavelength at f0.