1. 94 GHz Switching Circulator Tracy Shain Ryan Nichols Daniel Komisar Andrew Gadbois Advisor: Prof. Paul Siqueira

2. Develops microwave components from 18 - 300 GHz in satellite and millimeter wave communication Industry leader in millimeter wave communication Corporate headquarters in Northampton, MA Complete in-house machining and fabrication Allowing full facility access and use of high frequency equipment

3. What is a Circulator?

4. Example System: Continuous Transmission

5. Example System: Continuous Transmission with Receiver Protection

6. Circulator (RF Switch)

7. Why W-Band? ● Better resolution for remote sensing ● Smaller ● Higher bandwidth as percentage of center frequency

8. Design Responsibilities RF Design and Simulation Tracy Shain ResearchDaniel Komisar RF Measurements and Tuning Ryan Nichols Design of Driver Circuit Andrew Gadbois

9. Deliverables ● Design plans – Junction schematics from HFSS simulation – Driver circuit schematics from simulations – Material and spacial tolerances ● Test results/Final specs ● Empirical tuning instructions ● 94 GHz switching circulator

10. Specifications ● Bandwidth: 3% ● Center Frequency: 94 Ghz ● Isolation: 20 dB ● Insertion loss: 0.8 dB ● VSWR: 1.3:1 ● Switching Time: 10 ns ● Temp: -40°C – 85°C ● Driver circuit CMOS/TTL compatible

11. Design Alternatives Types of Switches:  Ferrites  PIN Diode  Mechanical Transmission: Waveguide Microstrip

12. Design Alternatives Types of Latching: No Latching Requires constant power to maintain magnetic fields Eg. Electromagnet with no field when there is no current Half - Latching Constant field in one direction, but requires constant power to reverse field Fully - Latching Short pulse of current in one direction is capable of rearranging the fields within the ferrite to reverse the direction of the magnetic field

13. Critical Analysis of Failure ● Insertion loss ● Frequency response ● Power handling ● Input/output impedance ● VSWR ● Magnetic Leakage

14. Schedule TaskSept.Oct.Nov.Dec. Research********************* RF Design************* Model 1******** Model 2******** Sim 1*** Sim 2*** Research Ferrite******* Order Ferrite********* Driver Design****************

15. Schedule TaskWeek 1Week 2Week 3Week 4 Driver Design*********** Layout Driver***** Order Parts***** Order Boards****** Assemble Driver***** Build Circulator********** January

16. Schedule TaskFeb.Mar.Apr. Test Circulator and Driver ********** Redesign / Tune Ferrite ********* Documentation and Report **********

17. MDR Specifications ● Complete Ferrite research ● Order material to allow sufficient lead time ● Complete microwave design and numerical tests - Ansoft Design and Simulation - Analyze 2 Design Alternatives - Test 94 Ghz Y-Junction Waveguide ● Preliminary Driver Design

18. Questions?