Antennas and RF Systems (EEMEM0015)
Coursework Overview
October 2025
1. Aim
The coursework requires the basic RF design and analysis of a common line-of-sight communications system, Direct Broadcast Satellite (DBS), operating in the Ku-band.
The aim is to design a ground-based satellite receiver system with the smallest antenna (i.e. lowest gain), whilst maintaining a Signal to Noise ratio (SNR) of 9dB.
2. Background
For any line-of-sight RF communications link, the Signal-to-Noise (SNR) performance of the system can be fundamentally expressed by the following equation:
The first part is transmitter and system related:
• pt Gt is the EIRP of the transmitter and this product will be defined through regulations
• B is the bandwidth of the system and would therefore relate to a particular channel bandwidth
• k is Boltzmann’s Constant (1.38 x 10-23 J/K) The last part is the path loss term:
• R is the (free space) distance between the transmitter and the receiver and hence their relative locations
• λ is the operating wavelength. The (central) operating frequency is therefore also system related.
The central part (G/T ratio) is the only factor under the ‘control’ of the antenna and RF designer and therefore the parameters here ultimately define the RF system performance:
• Gr is the Gain of the receiving antenna
• Tr is the receiver noise temperature at the interface between antenna and RF
circuitry. This is measured at the output of the antenna (before any feedlines) but antenna efficiency should also be included here.
• TAnt is the Antenna Noise Temperature that is a function of the directive gain of the antenna and the ‘brightness temperature’ of its surroundings.
Antenna parameters Gain, Efficiency and Matching therefore play a part in the transmitter ( Gt ) and the receiver (Gr ) as well as the antenna noise temperature (TAnt )
Amplifier parameters Gain, Efficiency, Matching and Noise Figure contribute to the transmitter (pt ) and also the receiver Noise Temperature (Tr ). Furthermore the latter is the result of multiple (subsequent) stages of RF circuitry (mixers, filters and amplifiers) rolled into a single parameter.
Atmospheric considerations are important. Precipitation will reduce signal levels and increase front-end noise, hence ‘doubly’ affecting the SNR.
3. Requirements
Figure 1 shows the components of the receiver architecture under consideration.
Figure 1. Simplifier receiver architecture.
The coursework is divided into 3 sections that are covered either in the online material or live lectures. These sections can be tackled over a series of weeks with a final report at the end.
• Full IF Amplifier design.
The IF frequency at the receive output can be anywhere between 0.8GHz and
1.4GHz. Use of AWR software tools for full amplifier modelling.
• RF link calculation.
Students will need to consider look angle and propagation distances; satellite antenna footprints; choice of antenna and front-end RF components; estimation of thermal noise and other factors affecting signal levels (such as rain attenuation). A SES-Astra satellite [https://www.ses.com/] will be used for the reference satellite.
• Ground-based antenna.
To fulfil the SNR requirement of 9dB, the gain of the antenna will need to bedetermined. Identify/justify a suitable commercial antenna to fulfil the requirement.
• Report.
Template-based report of 4-8 pages. Guidance will be given as to what should be covered in the template sections:
• Introduction. Aims and objectives.
• Amplifier design using AWR . Description of design, summary table and analysis
• Commercial Antenna. Description of antenna, summary table and analysis
• Overall system performance. Description of receiver system, summary table (with transmitter EIRP, path losses and all RF components) and analysis.
• Conclusions. Quantifiable outcomes. Identify other factors that could impact performance and hence form. part of future work.
Finally…
Given the number of different factors in the specifications and design, it would be expected that all report outcomes will be different in some way