Introduction



Integrated Front End Receiver for S-DARS Reception(Satellite Digital Audio Radio Service)AdvisorDr. Thomas WellerSenior Capstone ProjectFinal ReportUniversity of South FloridaElectrical Engineering DepartmentSpring 2013Team“Wireless Moguls” Peter KowalikYuriy Miroshnichenko U13859596 U44023635Table of Contents TOC \o "1-3" \h \z \u Introduction3Design Requirements PAGEREF _Toc354543062 \h 4Electronical PAGEREF _Toc354543064 \h 5Mechanical PAGEREF _Toc354543065 \h 5Miscellaneous PAGEREF _Toc354543066 \h 5Design Specifications PAGEREF _Toc354543067 \h 6Solution PAGEREF _Toc354543069 \h 6Amplifier PAGEREF _Toc354543070 \h 6Antenna Design PAGEREF _Toc354543071 \h 7Constraints PAGEREF _Toc354543072 \h 7Test Plan Document PAGEREF _Toc354543074 \h 8 Specific Test Plan Components PAGEREF _Toc354543075 \h 8Components to be Tested PAGEREF _Toc354543076 \h 8Requirements Document Matrix PAGEREF _Toc354543078 \h 9Antenna Design Considerations PAGEREF _Toc354543079 \h 10ADS Simulations PAGEREF _Toc354543081 \h 11Fabrication PAGEREF _Toc354543082 \h 12Alternative Antenna Designs PAGEREF _Toc354543084 \h 13ADS Momentum Visualization Tool Simulation PAGEREF _Toc354543086 \h 16Fabrication of Patch Antenna PAGEREF _Toc354543087 \h 17Pre Selective Filtering PAGEREF _Toc354543088 \h 17Band Pass Filter PAGEREF _Toc354543089 \h 17Amplifier Design PAGEREF _Toc354543090 \h 18Verification Measurements PAGEREF _Toc354543091 \h 18Conclusion PAGEREF _Toc354543092 \h 23 IntroductionAs engineers, one of our many duties is to be a part of the ever improving change and innovation that drives this world. Electrical engineering is a particularly attractive field for this reason, especially to individuals that have a burning desire to make an impact on history. Many major modern contributions came from multi-disciplined engineers that took the initiative to seek out opportunities to harness their knowledge in math, science, and engineering in new ways. They see a need, a problem, a way to make something better, or more affordable, and use their engineering abilities to find a solution. Successful application can oftentimes lead to more opportunity, growth, and potentially, a large enterprise with virtually limitless reward to oneself in all respects. This is the entrepreneurial spirit that influences many, including our group. Apart from getting a great capstone learning experience, this was also one of the motives behind our project. We saw an opportunity when we notices a large price and quality gap between two types of antenna’s, so we felt it would be worth a try to use our expertise and multi-disciplinary backgrounds to design a median product. Although like all, we also start from somewhat humble beginnings, but we hope that this senior project will act as a stepping stone into our future, inspiring us to take on greater engineering design projects, and other endeavors.So more specifically, for our project we designed a front end receiver for commercial SiriusXM radio. The three main modules of it are the antenna, bandpass filter, and a low noise amplifier (LNA). The goal of the project was to get a working model and integrating the components into our design to achieve a premium level of performance. Ultimately, we were able to successfully build a comparable product of a premium front end receiver, and within our budget limitations, allowing us to potentially offer it for a fraction of the price of the competitor.This document will provide a overview of our design progress throughout the semester.RequirementsWe have seen over the years how technology is evolving around us and how the capabilities of our devices such as cellphones have greatly improved in the past decade. The other thing that has been evolving is the SiriusXM which gives you access to crystal clear radio station no matter where you may be if you’re on a boat, in a car, or just listening to radio inside your home. The great thing about Sirius radio is they have over 170 channels which is more than you can get on your standard FM radio. The advantage of Sirius XM radio compared to such radio systems as FM is that Sirius uses satellites orbiting in space to transmit the information to earth where in FM you have towers set up in different places and you can easily loose signal of a radio station by going to another city. The problem that we were trying to solve by doing this project was to make an active antenna to be able to connect it to a factory SiriusXM radio to receive the signal from satellites and not have to spend as much as one hundred dollars if we were to buy a high grade antenna from a store. In order to achieve this we have to follow the requirements that are going to be set in this document to keep us on the right track and make sure that everything is considered especially the needs of the customers that are going to use this front end receiver in there radio setup.Electrical Specifications2.0.The operational frequency of the Sirius XM antenna must be in the band of the Sirius spectrum which is 2320MHz to 2345MHz.2.1.The voltage standing wave ratio (VSWR) must be below 3:1 or Better.2.2.The input impedance of the antenna must be 50 Ohms.2.3.The LNA should have a gain of 28 dB.2.4.The antenna must be left hand circular polarization (LHCP).2.5. The antenna without the LNA should have at least unity gain. 2.6. Input connector TNC Female. 2.7.Voltage input 3~5V 2.8. Current drawn by the LNA should be no more than 30ma Mechanical Specifications3.0. The overall weight of the active antenna must not exceed half of a pound3.1. The dimensions should not exceed 3″x3″x2″.3.2. The antenna must be water proof. 3.3. The antenna must have a magnet to be easily attached to a cars roof. Other Requirements 4.0. The antenna should not cost us more then $30 to build final design.4.1. The antenna needs to work with Sirius radios that are currently in use. SpecificationsIntroductionIn our project we are trying to achieve a left hand circular polarized antenna that will be connected to the Low noise amplifier and receive satellite signal which will then play music in your car from factory Sirius radio. The problem that we are trying to solve is to design the antenna and a low noise amplifier circuit that we will put together to get us the proper gain and a good radiation pattern of the antenna to achieve a good connection between our antenna and the satellites.SolutionFor our low noise amplifier we have built a circuit to compliment the mini circuits PSA-545+ which is a high gain and a low current that we need to have in our amplifier design. The Gain that we measured of our or amplifier circuit was around 18dB of gain. The antenna we have not built yet but we have many approaches that we can take on the antenna design the different types of antennas that we could built is a Quadrifilar Helix, turnstile, or patch fed 90 dugout phase.Schematic of our Amplifier DesignAntenna Design Implementation Attempts(by type) Quadrifillar Helix Turnstile Antenna Patch AntennaConstrainsParts availability could be an issue and getting them on time also the level of knowledge and experience that we have in our group. We also noticed that we don’t always get to use the Wami lab which has a limited amount of open hours so that we could accomplish all of our testing. Conclusion We have already started putting our project together and have seen positive results. Therefore we think we have all the proper mentality and knowledge that we need to complete this project. As of now we have a working low noise amplifier circuit and need to do more testing. Test Plan DocumentADVANCE \d 7Objectives tc "2.1 References " \l 2 The objective is to test our Sirius XM active antenna and verify that it is working to the specifications of our designed. Our intention to do this testing as we build our project and make sure that we stay within our requirements that we have set forth in the beginning of our design process in the requirements document.Testing Strategy tc "2.2 Definitions " \l 2The strategy that we want to take is to build our components separately because of the complexity of the project we need to test our components separately to be able to get the required testing done and then combine the components to build the complete active antenna. The testing is going to be done in several steps after the components are built they will be tested and verified to be working to the specifications in this document. Specific test plan components:Low Noise Amplifier Frequency of amplification (2.0)Gain 28 dB (2.3)Voltage Input 3~5V (2.7)Current drawn < 30mA (2.8)AntennaOperational frequency 2,320~2,345MHz (2.0)VSWR 3:1 or Better (2.1)Input impedance 50? (2.2)Polarization LHCP (2.4)Antenna must have at least unity gain (2.5)Input Connector TNC Female (2.6)ADVANCE \d 7Components tested tc "4. Documentation"Low Noise Amplifier AntennaBandpass FilterApproachADVANCE \d 7tc "5.1 Coding Standards " \l 2The Low Noise Amplifier is going to be tested using a Vector Network Analyzer to verify the gain of the amplifier at the desired frequencies. The current drawn by the amplifier is going to be checked with a Voltmeter. In order to do our testing on the antenna we can use a vector network analyzer to determine that it is performing to our specifications, we also intent to do radiation patterns of our antenna to verify that we don’t have any nulls in our patterns that might affect the signal strength at critical angles.Requirements Document MatrixElectrical Specifications2.0.The operational frequency of the Sirius antenna 2320MHz to 2345MHz.2.1.The voltage standing wave ratio (VSWR) must be below 3:1 or Better.2.2.The input impedance of the antenna must be 50 Ohms.2.3.The LNA should have a gain of 28 dB.2.4.The antenna must be left hand circular polarization (LHCP).2.5. The antenna without the LNA should have at least unity gain. 2.6.Input connector TNC Female. 2.7.Voltage input 3~5V 2.8. Current drawn by the LNA should be no more than 30mAMechanical Specifications3.0. The overall weight of the active antenna must not exceed one pound3.1.??????? The dimensions should not exceed 3″x3″x2″.3.2.??????? The antenna must be water proof. 3.3.??????? The antenna must have a magnet to be easily attached to a cars roof. Other 4.0.??????????????? The antenna should not cost us more than $30 to build final design.4.1.??????????????????????The antenna needs to work with Sirius radios that are currently in use. Antenna DesignFor the antenna design we needed to make a left hand circularlypolarized antenna(LHCP), we were suggested to try and make a patch antenna with two feedlines and feed one 90 degree out of phase. The patch antenna was used because we were only working with a percentage bandwidth of 1% and it is a good starting point for our project. By using a 5mm air gap in our design we could easily achieve the bandwidth of 25 MHz. This antenna design was made using the Advance Design System (ADS).Design parametersFor this design we calculated the following parameters for our antenna using Linecalc the parameters for are antenna are listed below (table1).CenterFrequency(MHz)Dielectric constantWidth of FeedlineWidth of Patch (mm)Length of Patch (mm)Wavelength ,λ (mm)Wavelength ,λ/2(mm)Wavelength ,λ/4 (mm)2332.54.33.083035.570.9735.4917.43Table 1Simulated antenna in (ADS) Usingthe parameters described above, simulations in Momentumwere performed.The results areshown in Figures.1 through 6Figure 1. Patch DesignFigure 2. |S11| simulation of patch antennaFigure 3.Axial Ratio Figure 4. Smith chart Figure 5. Simulated power 3dBiFigure 6. Simulated polarization of antennaFabricated AntennaThe antenna wasfabricated using 60 mil FR4 substrate with a 5mm air gap shown in Figure 7. Figure 7.Fabricated AntennaConclusion This antenna design showed a good frequency response in the band of interest. Some of the things observed for this design there was a sharp increase in the axial ratio in this antenna after 30 degrees from the boresight of the antenna and a lower than expected gain of 3dBi. After seeing that this was not the most optimum design to be utilized in our front end receiver we decided to still make a patch antenna but utilize a different design using a single feed point with perturbed edges.Alternative Antenna DesignFor this antenna design simply by adjusting the feedline offset away from the center of the patch LHCP can be achieved and a good axial ratio can be attained byadjustingthe patch widthandlength.Itwasfoundin simulationsthat the line insetdoes not havea significanteffect on the axial ratio. Since the AR could notbesimulated to be below 1dB bychangingallgeometrical parameters and changing substrate thicknesses and dielectricconstants, a new designwasconsidered because the overall axial ratio of the new antenna design was better than the first approach with two feed lines to the patch this design was chosen to be used in the final design of the front end receiver. The use of a perturbrectangularpatch with opposite diagonal corners truncated in our design helps to separate theorthogonalmodes and allow for LHCP Figure 8. Simulated antenna in (ADS)Figure 8. Patch antenna designFigure 9. |S11| Simulation of patch antennaFigure 10. Axial RatioFigure 11. Smith Chart Figure 12.Gain of Simulated patch is 6.55dBi Figure 13.Simulated polarization ADS Momentum Visualization Tool SimulationIsometric view Side viewFigure 14.ADS visualization tool simulates E fields in patch designLooking at the simulation in ADS Visualization we can see that the electric field rotates counter clock wise which verifies the Left Hand Circular polarization that we are trying to achieve in our design.Fabrication of Patch Antenna Figure 15.fabricated patch antenna Conclusion The new design of the patch antenna we were able to accomplish a higher gain and a better axial ratio of the antenna then the first design. The final parameters for the antenna that gave us the best result of return loss, axial ratio, and exhibit a left hand circular polarized radiation was 120 mils of FR4 substrate with a 60mils air gap.Pre Selective FilteringBand pass filter For this project is it crucial to use a bandpass filter in our design so we can filter unwanted signals that are outside our band. Looking at (Figure 16) we can see response ofbandpass filter over the frequency’s ranges. This filter covers the necessary band for our front end receiver and has an insertion loss less than 1.5 dB over the range of the filter bandwidth. Figure 16. Response of Bandpass FilterAmplifier Design The LNA amplifier used in our front end receiver system is a mini circuits 545 chip amplifier. In integration of the amplifier in our design we had to set the bias voltages to the amplifier and connect the 5V DC source to the amplifier that is delivered from the radio units connector also had to use capacitors at the input and the outputs of the amplifier to block the DC signal from damaging our amplifier.to verify the gain of the LNA we used a network analyzer and measured the gain of our LNA to be 18 dB.Verification MeasurementsWe wanted to verify the actual gain of the fabricated patch antenna and see if it was close to the simulated gain in ADS. The way we measured gain is we used gain by comparison. We set up our test by setting the vector network analyzer to S21 measurement and used a horn antenna for the transmit antenna and our calibrated reference antenna was a high gain horn which has a 10 dBi gain at the frequency of interest 2320 to 2345 MHz The measured gain in lab was plotted in excel shown in[Figure 17].Figure 17. Measured Gain Figure 18. S21 responses of gain measurement Figure 19. Gain by Comparison Measurement For the verification process of our final design test we set up a vector analyzer as our signal generator using a horn antenna as a transmit antenna and connected the front end receiver to the spectrum analyzer and measured the signal that was received by the front end receiver from the network analyzer source in dBm. for this experiment we wanted to measure different type of front end receivers to see how our design compared to other front end receivers. The transmitter and the front end receiver were places 1 meter apart during this measurement to see power level measured of different front end receivers measured[Figure 20].Figure 20. Power measurement of front end receiver Figure 21.Premium Sirius front end receiver power measured 2.31 dBm Figure 22. Power measured of our antenna and evaluation board LNA of -1.93 dBm Figure 23. Power measured of our antenna and LNA of -5.22dBm Figure 24. Power measured of standard front end receiver of -11.06 dBmWith this test we were able to confirm the performance of different front end receivers compare to our design. With the use of evaluation board we go the best result compared to the premium antenna and our front end receiver design showed a lower gain then the premium front end receiver so the LNA that we designed did not meet the objective gain for the overall design of the front end receiver. We suspect that we might have a problem with our components in the LNA design because of the frequency that we are working with the components could be more inductive or capacitive at high frequency.ConclusionWe were able to design and build a fully functioning front end receiver to successfully accept a SDARS signal. A video may be viewed of the working model on our YouTube page found on our website: wirelessmoguls.. After a semester’s worth of trial and error attempts, we were finally able to achieve specifications closed to our desired. That drawback was due to the fact that there was a little less gain at the amplifier. However, we still achieved making it a product worthy to bring to market and potentially make larger quantities of, as we hoped originally. Our objective to develop a front end receiver with specifications similar to the premium brand was met using the evaluation board of our amplifier design it shows that with correcting our amplifier design the objective would be met and built for a fraction of the cost of premium front end receivers. We also learned more about the science of integrating components and the process building a whole system. We got practical experience designing and developing a wireless device from scratch, which can be very valuable in the industry. It wouldn’t have been possible without our teamwork and each member’s multidisciplinary backgrounds. This was a very challenging senior design project. It bought together all of the skill we’ve acquired throughout our college experience at USF. Overall, this was a great capstone experience! ................
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