A method for designing a small antenna matched to an input impedance, and small antennas designed according to the method

摘要

A method for designing a high performance, small antenna that is matched to a required output impedance, does not require filtering, is simple and inexpensive to manufacture, and is easily integrable with an RF power amplifier- with minimum cost, minimum external components and minimum energy losses. The method includes finding a singular point ( 102 ) in the impedance vs. antenna geometrical dimension/wavelength ratio graph, the singular point ( 102 ) exhibiting a high very high positive reactance, setting the antenna geometry to match this point, and canceling the very high positive reactance (high inductance) resulting from this match by adding to the antenna a very small capacitance, preferably provided by at least one gap capacitor ( 202 ) The antenna is preferably a loop antenna ( 200 ), and both the antenna and the gap capacitor ( 202 ) ( 204 ) are preferably implemented by printing methods on printed circuit board or ceramic substrates. The antenna ( 200 ) may also be implemented in non-differential designs.