Dissertation in RF Engineering (Presented - 01-10-10)
- 1. Design of 3-dB Band Pass Filtered Power DividerSankarVelama --- 0926188MSc Mobile CommunicationsSupervisor : Dr. Kenneth Yeo
- 2. Aim & Objectives :To advance the present trend in RF/Microwave engineering & more specifically to design a 3-dB Band Pass Filtered Power Divider.
- 3. To achieve the response of the band pass filter & the power divider simultaneously.
- 4. To achieve desired circuit & microstrip layout.
- 5. To simulate the design & present it’s results.
- 6. To make the analysis & find out the future enhancements.Need for this Project Consider any balanced LNA with a band pass filter , normally used in satellite receivers, radiometers, transceivers & W-CDMA receivers.
- 7. The proposed diagram represents how the complexity of a conventional design can be reduced.Specification of the design
- 8. 3rd Order Band Pass Filter using Chebyshev prototype The normalised low pass parameters were calculated
- 9. Frequency & impedance scaling
- 10. Shunt only & Band pass transformation
- 12. External Quality factor, Qext
- 13. Circuit model implementationSpread Sheet for all the Calculations
- 14. Schematic of a 3rd order band pass filterAgilent ADS was used to design the circuit & microstrip layouts.
- 15. J-inverter model for 3rd order band pass filter The next part of the implementation is to convert schematic level in terms of j-inverter.Schematic for 3-dB Band Pass Filtered Power DividerSimulation response :1. Before optimization2. After optimization
- 16. Microstrip Layout Design The required geometries for microstrip design such as width & length were calculated using MS-Excel.
- 17. Using the above parameters, there are four different designs were developed.Design Procedure for Microstrip LayoutDetermine the desired shape & length of the resonator
- 18. Use the theoretical coupling coefficients to relate with the coupling spacing’s
- 19. Extract the external Q-factor in order to connect input & output ports
- 20. Build the final layout using all the previous steps.
- 21. Simulate the overall design and tune the physical layout to achieve desired value.Microstrip Design - 1Simulation Response
- 22. Microstrip Design - 2Simulation Response
- 23. Microstrip Design - 3Simulation Response
- 24. Microstrip Design - 4Simulation Response
- 25. ConclusionThis research represents one of the first efforts to advance the present trend in RF/Microwave engineering especially on balanced LNA designs.
- 26. The design & implementation of 3-dB band pass filtered power divider for circuit & microstrip layouts were executed successfully.
- 27. The agreement between the predicted & the obtained values of insertion losses (S21 & S31) & return loss (S11) were strong enough for fabrication.Future Research However, insights from this research can only provide a filtered power divider, whereas power combining is not possible due to the poor isolation between the output ports, hence this drawback can be consider for future research.Thank You...!