WORK Microwave’s Sensor & Measurement division is continuously expanding its scope towards new radio frequency (RF) sensor technologies and products.
The innovations are the result of self-driven projects or cooperations with partners in industry and academia. A current development based on the microwave transmission method is outlined below:
Many production lines demand for inline monitoring of water content in the product, but cannot provide a direct contact to it. Contacting the product may lead to defects or irregular quality.
To account for this problem, a contact-free radar type moisture sensor (RT-Sensor) is currently in development in addition to the existing split resonator (SR-Sensor) approach. The RT-Sensor allows for higher distances of up to 15 cm to the product.
The antenna and electronics are mounted at one side of the product while on the other side a simple metallic reflector is sufficient.
The electronics generates an RF signal that is emitted by an antenna towards the product. The RF signal passes through the product, is reflected at a metallic surface and passes the product again, before it is received by the same antenna. The signal is coupled out by a directional coupler and lead to a receiver port of the electronics.
Data processing is performed including a time-gate approach to suppress unwanted reflections. The moisture value of the product is derived by the amplitude and phase change of the signal. Dynamic distance variations between the antenna and the product during production do not impact the measurement result.
