V-band to baseband wideband heterodyne frequency down converter

Abstract

Recently, demand and interest in high-speed wireless communication has been increasing, and research on broadband wireless communication systems has been increased consequently. One of the most important considerations in configuring broadband wireless communication systems is the gain flatness, which greatly affects the quality of communications in systems where multiple single circuit blocks are nested and connected. However, gain flatness is difficult to obtain due to bandwidth limitations in heterodyne structures. In this paper, with the aim of securing good gain flatness in heterodyne structured frequency down conversion system, a frequency down converter consisting of two mixer is designed. The two mixers were designed to have an opposite gain slope within the bandwidth, so that each cancels the other's slope, making the overall conversion gain characteristic in the bandwidth flat. The RF mixer has 5dB rising gain slope within the bandwidth and has 1dB gain in the center of the bandwidth. The IF mixer has 4dB falling gain slope within the bandwidth and has 4dB gain in the center of the bandwidth. The frequency down converter, which is composed of 2 mixers, has 6dB peak gain in the bandwidth and 2dB gain flatness in the bandwidth.