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The wideband gain and voltage standing wave ratio (VSWR) performance of quad-ridged horn antennas in general are restricted due to the excitation of higher order modes in the coaxial to quad-ridged waveguide transition. This results in large gain variations vs. frequency and break-up of the radiation patterns at higher frequencies. In this paper, a quad-ridged horn antenna is presented with optimized radiation characteristics and VSWR performance. The performance of the antenna was optimized by separating the antenna into two subsections, viz. a coaxial to quad-ridged waveguide transition section and a flared quad-ridged horn section. The performance of each section was optimized individually using a numerical solver – CST Microwave Studio. Three possible configuration of the coaxial to quad-ridged waveguide transition section were considered and optimized. Four configurations for the flared quad-ridged horn section were also investigated. The best performing configuration from each one of the two section...

Double Ridged Guide Horn antennas are highly sensitive to tolerances in machining and assembly. This study shows that most of the sensitivity problems can be attributed to gaps formed between various subsections in the waveguide launcher assembly. The coaxial feeding section is especially sensitive to manufacturing tolerances. It was found that gaps between the ridges and feeding section causes deep resonances in the on axis gain. Due to the small tolerances involved, a highly detailed broadband simulation model of the antenna that includes a coaxial feeding section as well as an N-type connector had to be used in the investigation. The model is implemented in the electromagnetic simulation software package FEKO, which uses the method of moments (MoM) technique to calculate the electromagnetic fields. Gaps between the subsections of the waveguide launcher were implemented in the simulation model and compared to typical measured results. Excellent agreement between measured and simulated data is obtained. ...

A uni-planar balun that transforms from unbalanced coplanar waveguide (CPW) to balanced coplanar strip line (CPS) is characterized through simulation and measurement. The balun is tested in the normal back-to-back configuration, as a terminated single balun, and the magnitude and phase imbalance are also determined by using a 3-port test circuit connected to the balun. Etched bond wires are implemented to provide better manufacturing repeatability. A simple technique to correct the phase imbalance of the balun is introduced, and validated through port measurements of the balun connected to the 3-port test circuit, as well as radiation pattern measurements for the balun connected to an etched dipole.