Compact Circularly Polarized Composite Cavity-Backed Crossed Dipole for GPS Applications

Abstract

In this paper, we present a circularly polarized (CP) composite cavity-backed crossed dipole antenna for global positioning system (GPS) applications. We produce the CP radiation by crossing two dipoles through a 90° phase delay line of a vacant-quarter printed ring, which also has a broadband impedance matching characteristic. Two techniques, insertion of meander lines in the dipole arm and arrowhead-shaped trace at its end, are employed to reduce the sizes of the primary radiation element. The compact radiator is backed by a cavity reflector to achieve a wide CP radiation beamwidth. The proposed antenna exhibits a measured bandwidth of 1.450～1.656 GHz for a voltage standing wave ratio (VSWR) < 2 and 1.555～1.605 GHz for AR < 3-dB. At 1.575 GHz, the antenna has a gain of 7 dBic, a frontto-back ratio of 27 dB, AR of 1.18 dB, and 3-dB AR beamwidths of 130° and 132° in the x-z and y-z planes, respectively.

Single-Feed Composite Cavity-Backed Four-Arm Curl Antenna

“…The resulting antenna is characterized first with the ANSYS-Ansoft High Frequency Structure Simulator (HFSS) [16] and its simulated performance is then verified by measurements. In comparison with the previous wide-beam GPS antennas [14,15], the proposed antenna yields the same CP radiation performance with smaller antenna dimensions.…”

“…The condition for CP radiation mentioned in the subsection A can be obtained in two equal length dipoles with a single feed by using a pair of vacant-quarter printed rings [14,15]. Accordingly, this approach is applied to the four-arm curl antenna with the same number of turns for all arms in order to produce the CP radiation and direct matching to a single 50-Ω coaxial line.…”

“…A pair of vacant-quarter printed rings is employed in the feed of the radiator for direct matching to a 50-Ω coaxial line and to produce a CP radiation. The incorporation of the cavity-backed reflector [14,15] is a simple technique to improve the CP radiation characteristics in terms of 3-dB AR bandwidth and high-front-to-back ratio. The resulting antenna is characterized first with the ANSYS-Ansoft High Frequency Structure Simulator (HFSS) [16] and its simulated performance is then verified by measurements.…”

Compact Circularly Polarized Crossed Dipole Antenna With Chip Inductors and Square Rings Loading for GPS Applications

“…In [9], crossed dipoles consist of a top-loaded triangular and a filleted rhombic to achieve the required input impedance relations for CP radiation. In [10][11][12][13][14][15], CP radiation is produced by crossing two dipoles through a 90 • phase delay line of a vacant-quarter printed ring. Particularly in [15], the antenna employs insertion of meander lines in the dipole arms and shaping of the dipole arm end into arrowhead subtly to obtain a compact size for GPS application, whose plane dimension is 42 mm × 42 mm.…”

Single-Feed, Wideband, Circularly Polarized, Crossed Bowtie Dipole Antenna for Global Navigation Satellite Systems

“…3(a). The direct wave radiates from the radiator directly and the conditions for the CP radiation were obtained by double vacantquarter printed rings [9]. The reflected wave incorporated with the chosen slots between the adjacent bowtie arms (Fig.…”