Pulse Transmission And Reception Via Electrically Small Antennas Based On Super-regenerative Architecture

Pulse-based radio is widely used in various areas including short-range communication, radar target detection, ranging and localization etc. However, the wideband feature of the pulse signals constitutes a significant challenge to the RF front-end and antenna design. Traditional RF systems are designed in the frequency domain. Given specific power and frequency range of the signal, the antenna and RF front-end are considered as linear time-invariant elements. As a result, the system performance is constrained by the gain-bandwidth restrictions, leading to many difficulties in the design and implementation of wideband pulse-based systems.In this work, a scheme of transmitting and receiving pulse signals via electrically small antennas is introduced by taking advantage of the time-domain characteristics of the pulse signals. The scheme is based on a super-regenerative architecture and exploits the impedance and radiation features of electrically small antennas. Different from the conventional frequency domain technique, the scheme in this work employs a time-domain design method by modeling the electrical small antenna with an equivalent circuit. Based on the equivalent circuits, RF front-end circuits can be co-designed with the antennas, leading to a low-cost, low-complexity and miniaturized pulsed transceiver design and implementation. Specifically, the work accomplished is as follows:(1) By exploiting the impedance characteristics of electrically small antennas, a low-cost and miniaturized pulse receiving scheme is introduced and implemented by means of incorporating electrically small antennas into a super-regenerative oscillator design;(2) An electrically small patch antenna and its equivalent circuit model are designed and implemented, which is used to achieve the co-design and co-simulation of super-regenerative circuits and antennas;(3) By exploiting the impedance characteristics of electrically small antennas, a low-cost and miniaturized pulse generation and radiation scheme with high efficiency is achieved with the electrically small antennas being incorporated into a switched LC oscillator design;(4) The free space propagation is modeled by an equivalent circuit, which combined with the antenna equivalent circuits, is used to realize a unified simulation of the pulse transmitting and receiving systems. Based on the unified design and simulation methods, an experimental demonstration system is designed and implemented, with measured results showing that the proposed technique is promising for pulse communications under common modulations schemes such as the on-off keying(OOK).