R. Todd

Multiband reflector antenna for improved satellite communications in rural areas

The novel design of a circular waveguide feed structure for use with a Direct Broadcast Satellite (DBS) reflector dish that can operate in two frequency bands for HDTV, is presented. The dimensions of the waveguide are calculated from theory. The antenna is modelled and simulated in CST Microwave Studio™ with the addition of a dielectric to shrink one of the waveguides to reduce both size and cost. This antenna feed will have applications for those people in the UK and Ireland who do not receive a quality landline broadband service of at least 2 Mbps. The new DBS design will permit much greater bandwidth for multichannel HDTV and broadband duplex at greater than 2 Mbps via satellite to the home.

A dual band ridged waveguide feed structure for satellite television reception

The design and simulation of a dual band, coaxial waveguide feedhorn structure for a satellite reflector dish is presented using CSTs Microwave Studio™. The feedhorn operates on the satellite television frequencies, commonly referred to as the Direct Broadcast Satellite (DBS) frequencies of, 10.7–12.75, 19.7–20.2 and 29.5–30 GHz. The feedhorn structure consists of two separate waveguides that are placed inside one another and at the focal point of the reflector dish which will be illuminated with circular polarization from a geostationary satellite. The inner circular waveguide is filled with a dielectric material, Rexoilte™ that reduces the physical size of the waveguide but also serves to protect against moisture ingress and acts as a matching stub device. The outer circular waveguide is ridged in order to reduce the cut-off frequency for the first mode and to increase the bandwidth between the dominant TE11 mode and the second mode of operation, TM01. A reduction in overall size is seen compared with previous work.

Corrugated dual band waveguide and EM signal generators — An overview for future satellite communication possibilities

In this paper we present an overview of work carried out to design, manufacture and test a corrugated waveguide section for a feedhorn, suitable for a reflector antenna to receive digital satellite television. A system has been designed to carry circularly polarized waves in a two concentric waveguide system. Waveguide transitions are also designed, constructed and tested in linear polarization to permit the testing of the corrugated section. Initial results show that the signal generators measured performance is comparable to simulation results. We aim to focus on improving these results with a target return loss performance of −20dB across the band of 19.7–20.2 GHz.