ABSTRACT
Wearable printed active and tunable antennas are not widely presented in the literature. However, several types of microstrip antennas are widely presented in books and journals. Low profile compact active and tunable antennas are an important part of several communication, Internet of things (IOT) and medical systems. Printed active antennas possess attractive features such as low profile, flexibility, light weight, small volume and low production cost. A microstrip antenna’s resonant frequency is altered due to environment condition, different antenna locations and different system modes of operation. Wideband active and tunable wearable antennas for 5G systems, IOT and medical systems are presented in this chapter. A voltage-controlled varactor is used to control the antenna’s resonant frequency, as a function of the varactor bias voltage, at different locations on the human body. Amplifiers may be connected to the wearable antenna feed line to increase the system’s dynamic range. Low profile compact tunable antennas are crucial in the development of wearable human biomedical systems.
Active wearable antennas may be used in receiving or transmitting channels for 5G, IOT and medical applications. In transmitting channels, a power amplifier is connected to the antenna. In receiving channels, a low noise amplifier is connected to the receiving antenna. A matching network matches the amplifiers to the antenna.
