DBS Receiver System Presented By: Sarah Scharf, Pierre Desjardins,GuiPing Zhang, Peter Eseraigbo Supervisor: Prof. Barry Syrett Overview and Background
Operates in Ku Band 12-18GHz Design is based on Bell Satellite Receiver As of 2010 Bell TV had over 2 million satellitecustomers DBS Receiver Motivation Receivers are used in all communication systems
Cellular communication Military radar and navigations systems Television broadcasting Opportunity to develop design skills whichare directly applicable to the communicationindustry Significance of Project
Opportunity to create a basic receiver designand look for possible improvementsuggestions This receiver design can be used by futurestudents to investigate more efficient andcheaper receiver design options Satellite Receiver System
Diagram of our system: Project Management Each individual was assigned a component toresearch and design Conducted weekly group meetings Met with supervisor on an as-needed basis Communicated both verbally and through frequently Roles and Responsibilities
Pierre: Antenna system and band-pass filter Reflector dish and Antenna feed Name Expected Results Antenna Gain 34.5dBi 32.77dBi 3dB Beamwidth 3.5deg 4deg 10dB Beamwidth 5.5deg 6deg Roles and Responsibilities (cont)
Band-Pass Filter (12.25GHz GHz) Roles and Responsibilities (cont)
Gui: the two stage LNA is designed withmicrostrip transmission line and usedpseudomorphic high-electron- mobility transistors. The designedgain is 20 dB and noise figure is lowerthan 2 dB. Design LNA Methods and Techniques
Using ADS software; Designed with Microstrip transmissionlines instead of lump elements. Started from Stage one with lowernoise figure and then second stagewith high gain. Optimized gain, noise figure andstability in ADS environment. Challenges and Solution
How to maintain the circuit stability at themeantime achieving enough gain; Solution is by make a compromise betweengain and stability The minimum specified gain for this LNA is 20 dB Design Results Noise figure and stability
It only has lower than 2 dB noise figure. And the circuit is stable Design Results-Final Layout
This two stage LNA is expected to producethe required gain Roles and Responsibilities (cont)
Peter: GHz Dielectric ResonatorOscillator (DRO) Primary purpose of the oscillator is to generateand maintain aneeded waveform at a constant amplitude and specific frequency Antenna IF = LO - RF MIXER IF Filter Signal Processing IF RF LO BPF LNA OSCILLATOR RF = 12.5 GHz IF = 1.25 GHz LO = Local Oscillator IF = Intermediate Frequency RF = Radio Frequency LO = GHz LO = GHz Advantages of topology
Methods and Techniques Circuit Topology Topology uses a resonator coupled to microstrip line, functioning as a high-Q bandstop filter that couples a portion of the transistor output back to its input. Advantages of topology Very high unloaded Q (Severalthousand) lumped elements are limited to fewhundred Low phase noise (Better) Good output power Excellent temperature stability ofmaterial they are made from Matching Network Series Feedback DRO Circuit Implementation In ADS
Simulation done using large signal simulator Harmonic Balance Parallel ResonantCircuit withtransformer coupling Active Device (BJT) Matching Network Circuit Shematic Series Feedback DRO circuitin ADS Challenges and Solutions
Getting oscillator to oscillate Adding current pulse Achieving desired oscillation frequency Investigating what circuit components affectoscillator frequency. Trial and Error. Changing LC values and re- simulating until oscillation frequency was achieved. Results Roles and Responsibilities (cont)
Sarah: Active BJT Mixer Methods and Techniques BFU710 by NXP selected as active mixer component Chosen mixer topology Roles and Responsibilities (cont)
Challenges and Solutions I-V curve for BJT showing approximatebias point Mixer starting point Roles and Responsibilities (cont)
Results and Discussion Approximate layout Output Spectrum: Output voltage at 1.25 GHz Progress to Date Chosen and purchased active components
Design using ADS and HFSS Simulation of design Design layouts completed Send out layouts for manufacturing Next Steps Complete and test individual printed circuits
Complete second iteration of design andmanufacture if necessary Present final result in written report DBS Receiver Please stop by our poster for further technicaldetails. References -bell-tv-subscriber-spends-75-a-month/ ite_TV_Frequency_Bands.asp 98a6.pdf BLKG.html