RF transmitter for electrically short antenna

摘要

A synthetic-frequency RF transmitter is provided for transmitting an electromagnetic signal via an electrically short antenna. The transmitter comprises a reactive energy storage with an effective reactance adapted to form with the antenna a resonance circuit with a resonance frequency and a driver adapted to provide to the resonance circuit an electric transmission signal having an instantaneous frequency that varies in dependence on an information signal. The transmitter is characterized in that the transmitter is adapted to dynamically change the resonance frequency by changing the effective reactance in dependence on the information signal. Thus, the instantaneous pass-band of the resonance circuit may be controlled to substantially always comprise the instantaneous frequency of the electric transmission signal and thus of the electromagnetic signal.

主权项

1. A synthetic-frequency RF transmitter for transmitting an electromagnetic signal via an electrically short antenna, the transmitter comprising:
a reactive energy storage, having a capacitive component and/or an inductive component, with an effective reactance, adapted to form with the antenna a resonance circuit with a resonance frequency; and a driver adapted to provide to the resonance circuit an electric transmission signal having an instantaneous frequency that varies in dependence on an information signal, wherein the transmitter is adapted to dynamically change the resonance frequency by changing the effective reactance in dependence on the information signal, and the effective reactance is capacitive.