A microwave power sensor based on GaAs MMIC technology

Abstract

A novel structure for measuring the power of microwave signals is presented. It measures the microwave power coupled from the CPW line by a MEMS membrane. In this method, the signal is available during the power detection. The fabrication of the power sensor is compatible with the GaAs MMIC process. The design, fabrication and experimental results of this sensor are given. The experimental results show that the sensor has a reflection of less than −15 dB and insertion loss of less than 2.0 dB up to 12 GHz. The total sensitivity of such a power sensor is 10.4 µV mW−1 at 10 GHz frequency.

Characterization of packaged inline-type radio frequency microelectromechanical systems power sensors

“…Typically, the general principle to achieve inline RF MEMS power sensors is that a certain part of the transmitted RF power is extracted by some sensing agents and detected, e.g. an insertion power sensor [2], a capacitive power sensor [3], and coupling power sensors in our group [4], with the available RF signal during the power detection, but there is very little consideration of real applications. Currently, most of commercial power sensors are applied to microwave power meters as detection components like self-heating power sensors [5][6][7] and indirectly-heating power sensors [8][9][10], but they are termination devices compared with the inline sensors and the input RF signal is completely dissipated after the detection.…”

“…In our previous works, the basic inline coupling RF MEMS power sensors based on sensing a certain percentage of the incident RF power coupled by the MEMS membrane were reported in [4]. In order to obtain the good RF performance and the wideband frequency response, the coupling power sensors with the improved structures by modifying the gap size of the CPW line and adding the metal-insulator-metal (MIM) capacitors were proposed [11].…”

“…In Fig. 1(a), the principle of the power sensors consists of two steps [1,4,[11][12][13][14]: (1) a certain percentage of the incident RF power is coupled from a CPW line where the RF signal is transmitted, into two inputs of the additional CPW lines by the MEMS membrane; (2) the coupled RF power is absorbed by the termination matching resistors at the end of the additional CPW and converted into heat and finally resulted in output thermovoltages by the thermopiles, based on Seebeck effect. It should be noted that this MEMS membrane is suspended above the CPW and its anchors are connected to the two additional CPW signal lines, as shown in Fig.…”

A GaAs MMIC-based inline RF MEMS power sensor

“…Therefore, the most problems of both sensing principles are a trade-off between the microwave performance and the sensitivity. For solving the problem, L. Han et al [9] proposed a novel inline microwave power sensor for the measurement of a certain percentage of the incident microwave power coupled by a MEMS membrane suspended above a CPW line, based on Seebeck effect. The power sensor consists of two independent steps: the coupling step and the measurement step.…”

A Micromachined Inline-Type Wideband Microwave Power Sensor Based on GaAs MMIC Technology

“…The third principle couples a small ratio of the microwave power by a MEMS membrane which is suspended over a CPW line. The coupled microwave power is then converted to heat by the matched resistance and measured by the thermopiles [10]. This power sensor has the following two independent steps: 1) the coupled step and 2) the measurement step.…”