A new approach to nearly constant input impedance of self-complementary antennas

FIORINI, FRANCO; MORBIDEL, LEONARDO; COSTANZO CASO, PABLO A.

JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS

VSP BV

Año: 2020 p. 1 - 18

0920-5071

Conformal techniques, based on the covariance of Maxwell?s electrodynamicsunder the full conformal group in four spacetime dimensions,are discussed in relation with the constant input impedanceproperties of frequency-independent antennas. In particular, weshow that by applying suitable conformal transformations to existingself-complementary planar structures like logarithmic spirals, theconstant input impedance property is considerably improved, especiallyin the low-frequency domain, where it usually fails due to thelarge wavelength involved. This procedure enables to perform amore intelligent truncation with the aim to capture some of the propertiesleft behind in the cutting and to design realistic ultra widebandantennas with a more controlled value of the input impedance in thewhole operation range.