Abstract: A wireless RF front end circuit and a wireless signal boosting device are provided. The wireless RF front end circuit includes a first switch, a second switch, an adjustable amplifier circuit, and a detection circuit. The second switch is electrically connected to the first switch through a first path or a second path. The adjustable amplifier circuit is disposed in the first path between the first switch and the second switch. The detection circuit is electrically connected to the first switch and the second switch and configured to detect a transmitting signal, wherein the detection circuit configures the first switch and the second switch to enable the first path and disable the second path in response to the transmitting signal has been detected.

Abstract: A fiber-optic sensor for liquid-immersion detection includes an optical fiber and an interface material layer. The optical fiber has an angled physical contact (APC) surface. The interface material layer contacts with the APC surface. The interface material layer has a rough surface when in a dry state to produce a diffusion reflection. The interface material layer has a smooth surface to produce a specular reflection when the interface material layer absorbs a liquid in a wet state.

Abstract: A fiber-optic sensor for liquid-immersion detection includes an optical fiber and an interface material layer. The optical fiber has an angled physical contact (APC) surface. The interface material layer contacts with the APC surface. The interface material layer has a rough surface when in a dry state to produce a diffusion reflection. The interface material layer has a smooth surface to produce a specular reflection when the interface material layer absorbs a liquid in a wet state.