Millimeter-wave direct digital receiver

ix-port technology has been under development in the past twenty years as a new way to perform vector single/multi-port microwave network measurements. Instead of performing frequency conversion as in a conventional vector microwave network analyzer, the six-port network analyzer acquires the vector ratio of reflected/outgoing waves by reading a set of microwave power levels at four of its six ports. A convenient calibration procedure ensures the same order or even better accuracy than conventional automatic vector microwave network analyzers such as the HP8510 and Wiltron 360.;In recent years, the millimeter wave band such as 38GHz band has become an attractive choice to personal communication services (PCS) backhaul in recent years due to vast spectrum availability and excellent frequency reusability. Unfortunately the cost of mm-wave receivers are in general much higher than their low-end microwave counterparts. Therefore cost reduction becomes a key factor in its competitiveness.;This thesis describes work on the proof-of-concept of a new digital receiver using six-port technology. Following is a summary of the original contributions made by the author in close collaboration with his research director, professor Renato G. Bosisio: (1) innovation of the concept of Six-Port amplitude/phase/frequency discriminator (SPD), which enables non-coherent detection and the proposal of the new six-port direct digital millimeter-wave receiver (DMR) scheme based on the SPD concept. (2) Computer simulation of the performance of the proposed DMR in comparison with conventional I-Q receiver. The new DMR achieves comparable performance as super-heterodyne digital receiver, and is much superior to I-Q direct conversion digital receiver. A good agreement between computer simulation and measurement results has been achieved. (3) Measurements of the six-port receiver to validate the feasibility of the new scheme. Set-up of a demonstration system for real time bit error rate measurement and constellation display. This system is capable of dealing with both coherent and differential PSK modulations up to 16QAM. (4) Development of a new calibration procedure: Dual-tone calibration especially the DMR. The new calibration procedure uses the received signal as the source of calibration and requires no external standard or special hardware. Same order of accuracy as standard six-port calibration methods is achieved. (5) Development of a 'soft phase reference' method of coherent PSK detection. (6) Development of a new method for linearization of the diode power detector: Dual-tone diode detector calibration.;In addition to the work mentioned above, great efforts have also been made to: (1) Implement the digital processing algorithms for DMR in the C language. (2) Setup and debug (both hardware and software) the real-time demonstration/measurement system. (3) Design and measure the six-port circuits of the DMR using MHMIC technology and initiate similar work for MMICs.;It is concluded that the new six-port DMR promises to be a cost-effective alternative to the conventional super-heterodyne digital receiver in various small or medium capacity communication systems. However, when a very large dynamic range (e.g.