Cylindrical metallized-ceramic antenna for receiving circularly-polarized waves, e.g. from GPS satellites, includes printed metallized antenna elements, balun and matching circuitry

摘要

The ceramic body has a dielectric constant of 20 or more and its surface carries a printed metallized ring with four electrodes spiraling along the surface of the ceramic. Similar pairs of electrodes (21, 24; 22, 23) have differing extents, the difference amounting to a quarter wavelength at the operating frequency, for reception of circularly-polarized waves. The design forms a quarterwave vertical antenna with counterpoise, with a built-in balun and transformer or other matching circuit. This transfers the signal between the unbalanced and balanced systems, and matches the impedances. Continuous bores are provided for connection terminals between the circuit and metal ring.