Conical Beam Antenna Research Articles

Research on circularly polarized conical-beam antennas

This antenna is intended for communication between a stationary satellite and mobile stations, and is designed to possess circularly polarized conical beams. It generates a beam in the desired direction, by means of changing the inclination angle of the linear-antenna elements, and the spacing between the antenna elements, without phase shifters. The antenna inclination angle (/spl alpha/), the antenna length (e), the distance between antenna elements (d), and the radius of the circular reflector (R), are adopted as parameters, and optimum values for the directivity of the research objective are obtained by calculation. Four elements of the antenna are fed by in-phase signals, the distances between elements are set to appropriate lengths, and by providing spatial phase differences of 90/spl deg/, circularly polarized waves are obtained. The antenna elements are fundamentally monopole radiators. Ultimately, the antenna parameters were determined as follows: /spl Lscr/=0.64/spl lambda/ (120 mm), R=0.43/spl lambda/ (80 mm), /spl alpha/=45/spl deg/, and d=0.48/spl lambda/ (90 mm). In the calculation, the frequency was set to 1.6 GHz. It was seen that the beam radiation intensity took the maximum value in the angular range of /spl theta/=30/spl deg/ to 60/spl deg/, and that the /spl theta/ and /spl phi/ components of the electric field were approximately equal. In other words, the radiated waves were circularly polarized. An experiment for measuring the directivity of the circularly polarized conical-beam antenna was carried out by using four monopole antennas, and the effectiveness of the theoretical analysis was confirmed. Experiments were carried out for the impedance and directivity.

Improved form of backfire bifilar helix conical beam antenna

The nonresonant-length backfire bifilar helix is often used as a vehicle satcom antenna, as it has a circularly polarized conical beam with azimuthal symmetry. Some antenna configurations, however, exhibit poor back-lobe levels. It is shown that radiation patterns can be significantly improved by correct termination of the helix. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 14:278–280, 1997.

Circularly polarized conical beam antennas

AbstractA small and lightweight antenna was developed which generates a circularly polarized conical beam in the desired direction by changing the incline angle of the linear antenna elements and the spacing between the antenna elements without phase shifters. the experiment for directivity of the circularly polarized conical beam antenna was carried out by using four monopole antennas, and the effectiveness of the theoretical analysis was confirmed.Next, experiments were carried out for the impedance and directivity with representative dimensions. the gain in the maximum direction was 4.5 dBi with an axial ratio of less than 2 dB and a standing wave ratio of less than 1.2.