Electrically short active antennas for M-sequence UWB systems

Antennas are key elements of every radio device. As their dimensions are proportional to the operational wavelength, they are becoming the limiting element for handheld devices operating at lower frequencies. In this article, the novel concept of active receiving and transmitting antennas is proposed for an M-sequence UWB (ultra wide band) ground penetrating radar (GPR) to minimize dimensions, complexity and costs of the antennas. Radiation principles of selected electrically short antennas are described and appropriate active circuits are designed as well. Their performance is verified by measurements in the UWB system. Using the electrically short antennas with active circuits designed in this work, 8 dB higher received signal level has been achieved in lower part of the frequency band while reducing costs, dimensions and weight of the antennas approximately 10-fold.