Ultra-Wideband Constant-Beam Feed and Reflector Antenna Designs
Project no. 26311 · Status: Kapanmış (Yayın bekleniyor) · 2023
Summary
<p>Ultra-wideband (UWB) systems are a developing field, that has been studied for a long time and still maintains its importance. It provides versatility to the system and also allows simultaneous usage of a wide frequency band. It has many application areas such as radio astronomy, broadband communication, measurement systems, satellite tracking, radar systems etc.. Especially in radio astronomy, antennas which used for more sensitive measurements, should have ultra-wideband and high gain characteristics, for example, when used for very long baseline interferometry (VLBI) observations. This is possible by feeding the reflector with a antenna which has constant 10 dB beamwidth and stable phase center.</p><p><br></p><p>In this project, the optimum solution for a feed antenna with a constant beam characteristic, designed for use in wide-band reflector antenna systems such as radio telescopes, ultra-wideband communication systems, and direction estimation and measurement systems, has been studied. The design of wide-band dual-polarization quadruple-ridge horn antenna (QRHA) is presented.</p><p><br></p><p>One of the most important criteria in designing an ultra-wideband antenna is the design of the back cavity part, which suppresses the generation of higher-order modes that affect radiation characteristics of the antenna. Solutions have been studied for suppressing higher-order modes by up to 20 dB over an ultra-wide bandwidth using conical and pyramidal back-cavity structures. The ridge structures of the horn antenna were defined using a three-dimensional spline profile, and studied to achieve the desired radiation characteristics.</p><p><br></p><p>In the ultra wideband antenna design, a stable beam characteristic was obtained over the 1.3–19 GHz (14.6:1) frequency range, especially in the electric field plane. The designed antenna was manufactured in 5 parts using 3D metal printing technology and assembled by screwing them together. In addition, a printed circuit board was designed for the structure manufactured with a 3D resin printer and coated with conductive paint. The simulated and measured results have been compared. Additionally, based on the antenna measurement results, the possible reflector antenna performance has been evaluated.</p>