Theoretical and Experimental Investigations of an Integrated Microwave Power, Frequency, and Phase Detector for X-Band Applications

Abstract

In this article, we present an integrated microwave power, frequency, and phase detector by GaAs monolithic microwave integrated circuits technology. The novelty of the reported detector is carefully designed by cascading a micromachined six-port coupler, a power divider, three power combiners, and four thermoelectric power sensors to realize microwave power, phase, and frequency detection. Compared with previous study, the reported microwave integrated detector has a more compact design and high-power-handling capacity. The advantage of the proposed technique is that the three parameters (power, frequency, and phase) of microwave signals are directly measured via the output of the thermovoltage. This makes the integrated microwave detection system more suitable for systems with complex requirements, such as radar systems. The experimental results demonstrate that the output thermovoltage and incident microwave power exhibit good linearity over a dynamic range of 0.1–1000 mW. Also, the measured sensitivities are 22.9, 27.2, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$33.7~\mu \text{V}$ </tex-math></inline-formula> /mW at 8, 10, and 12 GHz, respectively. A new method based on phase comparison is proposed for frequency detection. Also, the measured sensitivity is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9.42~^{\circ }$ </tex-math></inline-formula> /GHz over <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${X}$ </tex-math></inline-formula> -band. By introducing the reference signal, the function of phase detection is achieved based on the principle of vector synthesis over a dynamic range of 0°–360°. Also, the measured sensitivity is better than 98.38 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{V}$ </tex-math></inline-formula> /° at 500 mW. Furthermore, an integrated detection model is also proposed based on the microwave network analysis. The experimental results agree well with the proposed model. The results would be beneficial to improve future microwave integrated detector designs.