Broadband RF Adaptive Antenna With Automatic SWR Control by Using MEMS-RF Technology and Microcontroller Process

This article considers the possibility to create an automated antenna according system, for a broad spectrum of radiofrequency, in order to obtain a optimum tuning between the impedance of the final stage of radiofrequency and the broadcast antenna, based on the reduction of the standing wave ratio parameter, (SWR). Although there are a lot of technical solutions for this problem, the proposed solution uses an MEMS-RF type element and a PID regulator. The tuning element or the actuator is a variable condenser built using MEMS technology, which provides a variable tuning for the antenna depending on the output voltage generated by the microcontroller. The voltage generated by the microcontroller is calculated in order to minimize an analogic voltage, the SWR. The automated tuning function will be reached using a software PID, implemented in an 8-bit microcontroller, which will optimize the broadcast and tuning parameters of the antenna in the working bandwidth. The schematic of the hardware, of the tuning software, and PID controller response of the automated control system are presented.