By Professor Syed Idris Syed Hassan Sch of Elect. & Electron Eng Engineering Campus USM

1. Microwave Circuit Design By Professor Syed Idris Syed Hassan Sch of Elect. & Electron Eng Engineering Campus USM Nibong Tebal 14300 SPS Penang

2. Introduction • 10 weeks lecture + 4 weeks ADS simulation • Assessments :8 tests + 2 ADS assignments + 1 final examination • Class : 9.00- 10.30 lecture 10.30-11.00 rest (tea break) 11.00-12.30 lecture 12.30- 1.00 test

3. 06/04/02 Morning 20/04/02 Morning 27/04/02 Morning 04/05/02 Morning 11/05/02 Morning 18/05/02 Morning 25/05/02 Morning 08/06/02 Morning 15/06/02 Morning 22/06/02 Morning 29/06/02 morning 06/07/02 Morning 20/07/02 Morning 27/07/02 Morning Dates

4. Syllabus • Transmission lines • Network parameters • Matching techniques • Power dividers and combiners • Diode circuits • Microwave amplifiers • Oscillators • Filters design • Applications • Miscellaneous

5. References • David M Pozar ,Microwave Engineering- 2nd Ed., John Wiley , 1998 • E.H.Fooks & R.A.Zakarevicius, Microwave Engineering using microstrip circuits, Prentice Hall,1989. • G. D. Vendelin, A.M.Pavio &U.L.Rohde, Microwave circuit design-using linear and Nonlinear Techniques, John Wiley, 1990. • W.H.Hayward, Introduction to Radio Frequency Design, Prentice Hall, 1982.

6. Transmission Line

7. Equivalent Circuit R L R L C G Lossy line Lossless line

8. Analysis Kirchoff current law From Kirchoff Voltage Law (b) (a)

9. Analysis then Let’s V=Voejwt , I = Ioejwt Therefore b a Differentiate with respect to z

10. Analysis The solution of V and I can be written in the form of c d where and Let say at z=0 , V=VL , I=IL and Z=ZL Therefore f e and

11. Analysis Solve simultaneous equations ( e ) and (f ) Inserting in equations ( c) and (d) we have

12. Analysis and But Then, we have * ** and

13. Analysis or Or further reduce For lossless transmission line , g= jb since a=0

14. Analysis antinode Standing Wave Ratio (SWR) Reflection coefficient node Ae-gz Begz Voltage and current in term of reflection coefficient or

15. Analysis For loss-less transmission line g = jb By substituting in * and ** ,voltage and current amplitude are g h Voltage at maximum and minimum points are and Therefore For purely resistive load

16. Analysis Other related equations From equations (g) and (h), we can find the max and min points Maximum Minimum

17. Important Transmission line equations Zin ZL Zo

18. Various forms of Transmission Lines

19. Parallel wire cable Where a = radius of conductor d = separation between conductors

20. Coaxial cable b a Where a = radius of inner conductor b = radius of outer conductor c = 3 x 108 m/s

21. Micro strip Conducted strip t Substrate er he w Ground t=thickness of conductor

22. Characteristic impedance of Microstrip line w=width of strip h=height and t=thickness Where

23. Microstrip width For A>1.52 For A<1.52

24. Simple Calculation Approximation only

25. Microstrip components • Capacitance • Inductance • Short/Open stub • Open stub • Transformer • Resonator

26. Capacitance Zoc Zo Zo For For

27. Inductance ZoL Zo Zo For For

28. Short Stub Zo Zo Zo ZL Z

29. Open stub Zo Zo Zo ZL Z

30. Quarter-wave transformer l/4 x ZT ZL Zo Zo Zmx/min At maximum point q in radian

31. Quarter-wave transformer at minimum point q in radian

32. Resonator • Circular microstrip disk • Circular ring • Short-circuited l/2 lossy line • Open-circuited l/2 lossy line • Short-circuited l/4 lossy line

33. Circular disk/ring feeding a a * These components usually use for resonators

34. Short-circuited l/2 lossy line Zin = series RLC resonant cct Zo b a =nl/2 where

35. Open-circuited l/2 lossy line Zin = parallel RLC resonant cct Zo b a =nl/2 where

36. Short-circuited l/4 lossy line Zin = parallel RLC resonant cct Zo b a =l/4 where

37. Rectangular waveguide b a Cut-off frequency of TE or TM mode Conductor attenuation for TE10

38. Example Given that a= 2.286cm , b=1.016cm and s=5.8 x 107S/m. What are the mode and attenuation for 10GHz? Using this equation to calculate cutoff frequency of each mode

39. Calculation TE10 a=2.286mm, b=1.016mm, m=1 and n=0 ,thus we have Similarly we can calculate for other modes

40. Example TE20 TE11 TE01 TE10 6.562GHz 13.123GHz 14.764GHz 16.156GHz Frequency 10Ghz is propagating in TE10.mode since this frequency is below the 13.123GHz (TE20) and above 6.561GHz (TE10)

41. continue or

42. Evanescent mode Mode that propagates below cutoff frequency of a wave guide is called evanescent mode Wave propagation constant is Where kc is referred to cutoff frequency, g is referred to propagation in waveguide and b is in space When f0< fc , But g = a +jb a=attenuation b=phase constant Since no propagation then The wave guide become attenuator

43. Cylindrical waveguide a TE mode Dominant mode is TE11

44. continue a TM mode TM01 is preferable for long haul transmission

45. Example Find the cutoff wavelength of the first four modes of a circular waveguide of radius 1cm 2nd mode Refer to tables TM modes TE modes 3rd &4th modes 3rd &4th modes 1st mode

46. Calculation 1st mode Pnm= 1.841, TE11 2nd mode Pnm= 2.405, TM01 1st mode Pnm= 3.832, TE01 and TM11

47. Stripline b w

48. Continue On the other hand we can calculate the width of stripline for a given characteristic impedance

49. Continue Where t =thickness of the strip