MMIC lumped and transversal filter with LC tuned amplifiers

This paper presents a modular approach for the design of MMIC lumped and transversal filter with LC tuned amplifiers. The filtering improvement due to the introduction of LC tuned amplifier modules (LCTAM) as the transversal element on the conven­tional lumped and transversal structure is illustrated by comparing the performances of a single LCTAM and double LCTAM filters with a conventional one. In order to demonstrate the novel filter usefulness three filters with two transversal sections were implemented with the same typical 0.5 um GaAs MMIC technology (a conventional, a single and a double LCTAM). It is shown that when we increase the number of LCTAM the rejection increases, however the chip area and complexity also increase. For a 1.54GHz centre fre­quency filter, a good compromise is the double LCTAM. This solution on the lower stop band (-250MHz) has 15dB more attenuation than the other two filters and on the upper stop band (+250MHz) has 17dB and 20dB more attenuation than the single LCTAM or conventional filter topology, respectively.