| A new approach is proposed in this paper to generate and radiate pulse signals by exploiting thetime-domain characteristics of coupled resonant circuits and the input impedance characteristics ofelectrically small antenna. Different from traditional methodologies in which pulse generating circuitsand transmitting antennas are designed separately, this new approach incorporates electrically smallantennas into the design of resonant circuits, leading to a co-design of pulse generation and radiationsystem. Pulse signals are generated by appropriately controlling the coupling between resonantcircuits, and subsequently radiated from the antenna. The proposed design eliminates the needs forcomplex active elements in generating pulses and is able to adopt electrically small antennas asradiating elements. As a result, it provides a new way of implementing pulse transmitters with lowpower, low cost and compact form factor. Specifically, this work comprises the following:(1) The principle of operation of the proposed pulse generating method is explained. Typicaldesigns of generating pulse signals via switched coupling of two resonant circuits are illustrated.(2) The performance of the proposed circuit in terms of pulse width and pulse amplitude isanalyzed. Experiments are carried out to verify the performance of the design, based on which, theimproved designs are proposed and analyzed.(3) Input impedance characteristics of electrically small antennas are introduced. Equivalentcircuit modeling and transient simulation methods are described, based on which, effects of non-idealfactors are also discussed.(4) Based on the results of simulation, experimental verification is performed with the selectionof a10-cm dipole antenna and a loop antenna. With these antennas, two types of pulse radiationsystems are built. The measured results show that pulse signals can be effectively generated andradiated, which validates the feasibility of the proposed design. |
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