MotivationSystems OverviewSystems OverviewPreliminary sketchRequirementsMicrowave CircuitryChosen CircuitOptimization ResultsParabolic Dish SupportCost AnalysisRequirements Theoretically AchievedImprovementsRecommendations to MITSETWhat We’ve Learned16.810 IAP 2007 M1: Microwave Beam SourceM1: Naïve About Optics Team16.810 IAP 2007 M1: Microwave Beam SourceMotivationMITSET Power Beaming Competition• Primary focus of competition is power beaming• Microwave energy chosen for efficiency and scalability• Needs to supply an adequate power supply to rectennas• Needed a system that could easily be assembled/disassembled• High efficiency and cost effectiveness are the primary targets of project16.810 IAP 2007 M1: Microwave Beam SourceSystems OverviewDesign divided into three subsystems• Dish– Utilizes a pre-made satellite dish for simplicity and cost effectiveness– Needed to collimate the microwave energy– Needs to be fast and easy to assemble around the ribbon– Needs to be stable as well as level• Microwave horn support– Designed to hold the microwave horn over the center of the dish– Has an adjustable height to allow for an adjustable focus– Has to be rigid enough to support magnetron and horn and precisely place them over the dish16.810 IAP 2007 M1: Microwave Beam SourceSystems Overview• Microwave Circuit– Provides microwave energy for climber– Circularly polarizes the microwave energy– Transfers to Climber– Needs to be as efficient as possible– Uses a magnetron mated with a polarizer, and a horn to project energy16.810 IAP 2007 M1: Microwave Beam SourcePreliminary sketchRibbonRibbon MastCommandand ControlClimberRectennaBeam16.810 IAP 2007 M1: Microwave Beam SourceRequirements• Us optimists had two levels…• Functional:– Transferred power amount (400W), duration (50s), destination (10 to 60m)– Components on climber weight (<8.5kg) and more (rulebook)•Constraints– Transferred power polarization (circular)– Safety regulations– Laws of physics•Interface– Power Source– Climber ribbon anchor– Spectator and operator distances– Storage size– Assembly time• Optimization variables: Cost, Output Power16.810 IAP 2007 M1: Microwave Beam SourceMicrowave Circuitry• Design Options:–Source:• Helical• Magnetron– Transmission:• Coax• Waveguides– Polarisation:• Fresnel/Moony Rhomb• Quarter Wave Plate• Quadrature Coupler• Variable Length Branching– Beam widening:•Horn• Helical• Calvin Feed– Reflection• Offset• Cassegrain• Conical• Direct– Collimation• Field Choice• Forward/Backward• Beam Broadening– Boundary mitigation:• Crystals• Dielectrics• Difffuse beam16.810 IAP 2007 M1: Microwave Beam SourceChosen Circuit16.810 IAP 2007 M1: Microwave Beam Source16.810 IAP 2007 M1: Microwave Beam SourceOptimization ResultsEfficiency: 8%(back of the envelope: 14%)16.810 IAP 2007 M1: Microwave Beam Source16.810 IAP 2007 M1: Microwave Beam SourceWigi-wigi technology…Proves to be pretty stable.Circuitry Support16.810 IAP 2007 M1: Microwave Beam SourcePositive sides:1) Very light weight.2) Greater stability3) Can be put together pretty fast.4) Minimal air resistance.5) Easy to make, and cheap.Negative sides.1) Still have to figure out a way to make the y-axis variable, as desired.2) Unstable weight distribution (40” X 63”)16.810 IAP 2007 M1: Microwave Beam SourceParabolic Dish Support• Used to collimate microwaves• 120 inches in diameter• 20 inches deep• Pre-manufactured dish• Divided into 4 sections– 3 legs per section• Free standing sections• Simple design for quick assembly16.810 IAP 2007 M1: Microwave Beam Source16.810 IAP 2007 M1: Microwave Beam SourceCost Analysis16.810 IAP 2007 M1: Microwave Beam Source• No level 2• Functional:– Transferred power amount (400W), duration (50s), destination (10 to 60m)– Components on climber weight (<8.5kg) and more (rulebook)•Constraints– Transferred power polarization (circular)– Safety regulations– Laws of physics• Interface– Power Source– Climber ribbon anchor– Spectator and operator distances– Storage size– Assembly timeRequirements Theoretically Achieved16.810 IAP 2007 M1: Microwave Beam SourceImprovements• Polarization (Rectenna Related)• Beam blockage losses• Software use• Beam source and signal type• Beam directionality losses• Beam Collimation: variable reflector height• Play with the “wigi-wigi”, to figure out the optimum binding for perfect stability.• Unstable weight distribution (40.3” X 63”)• Improve stability, by proper load distribution (depends on new configuration)16.810 IAP 2007 M1: Microwave Beam SourceRecommendations to MITSET• Redesign incorporating Mr. Willwerth’s rather nice ideas• Perform Thermal Analysis• Comsol would be nice…• Review design by fresh person before testing• Test in sections before all up:– Magnetron alone– Waveguides + optimize– Waveguides + emitter– Reflector– Waveguides + reflector + optimize– Waveguides + receptor antennae– Reflector + receptor antennae16.810 IAP 2007 M1: Microwave Beam SourceWhat We’ve Learned• Trust measurements over specs• Don’t trust specialists• Trust specialists• Simplest design works best• There’s plenty to know about microwaves. What actually matters for implementation is tiny, but it’s hard to find out what it is.• It’s possible to do crazy things in one month. It’s hard to do them