Analysis and Design of a Novel $\times$ 4 Subharmonically Pumped Resistive HEMT Mixer

In this paper, a novel topology of an HEMT-based subharmonically pumped resistive mixer (SHPRM) is presented, i.e., the times4SHPRM. The presented topology requires only a quarter of the local oscillator (LO) frequency compared to a fundamentally pumped mixer (e.g., 15 instead of 60 GHz in a 60-GHz system). This reduction in required LO frequency provides a significant reduction in complexity of the overall radio front-end and reduces the dc power consumption as well as the occupied chip area. Thus, the times4SHPRM provides a significant cost reduction for a millimeter-wave system. Furthermore, the times4SHPRM can be used for both up- and down-conversion and it can be implemented in any field-effect transistor technology. The principle of the times4SHPRM is presented and wave analysis is applied in order to investigate the fundamental limitations of this mixer topology. For an evaluation of the times4SHPRM topology, three different monolithic microwave integrated circuits (MMICs) were designed and manufactured in the same MMIC metamorphic HEMT technology. Besides measured performance of the times4SHPRM, a traditional times2SHPRM and a single-ended resistive mixer were implemented and their performances are presented and compared. All of these MMICs operate with a 60-GHz RF frequency and employ LO signals close to 15, 30, and 60 GHz, respectively.