Power-Efficient High Intercept-Points Mixers for Wireless Communications

A unified approach of designing cost-effective, power-efficient and high intercept point passive double balanced mixer (DBM) is reported. This work is based on switching devices as a mixing cell (dual FETs) where gate´s capacitances are resonated by using hybrid resonance network for minimization of LO power level and nonlinearity of the mixing cell. The passive reflection FET mixers based on present approach can operate with low noise figure and high dynamic ranges without the need of excessively high LO drive level. This paper is based on patent pending approach that gives input intercept points (IIP₃) in excess of 40 dBm and conversion loss less than 9.5 dB with the LO power typically 17 dBm for the frequency bands (RF: 650-1500 MHz, LO: 700-1700 MHz, IF: 50-200 MHz). The interport isolation is improved by minimizing signal leakage between ports through amplitude and phase cancellation techniques, and is better than 30 dB for broadband applications. To our knowledge, the mixer circuits reported in this work exhibit best performance (for this class of circuits and given size and cost) to date, and easily amenable for integration in MMIC form. The circuit topology is not limited to these frequencies, and can be easily extended for other frequency band to meet the requirement of present and later generation of communication systems