The document describes a virtual faculty development programme on antennas and microwave engineering held from June 22-26, 2020. It is presented by Dr. S. Asha and covers five units: introduction to microwave systems and antennas, radiation mechanisms and design aspects, antenna arrays and applications, passive and active microwave devices, and microwave design principles. The agenda covers topics such as microwave frequency bands, applications, antennas, antenna parameters, and the Friis transmission equation.

1. VIRTUAL FACULTY DEVELOPMENT PROGRAMME
ANTENNAS AND MICROWAVE ENGINEERING
(22.6.2020-26.6.2020)
INTRODUCTION TO MICROWAVE SYSTEMS AND ANTENNAS
PRESENTED BY
Dr. S. ASHA,
PROF/ECE/SEC

2. ANTENNAS AND MICROWAVE ENGINEERING
• UNIT-1 : INTRODUCTION TO MICROWAVE SYSTEMS AND ANTENNAS .
(Dr.S.ASHA /PROF/SEC)
• UNIT-II : RADIATION MECHANISMS AND DESIGN ASPECTS .
(Mr.C.MAHENDRAN /ASST.PROF/ACGCET)
• UNIT-III : ANTENNA ARRAYS AND APPLICATIONS .
(Dr.A.AMSAVENI /PROF/KCT)
• UNIT –IV : PASSIVE AND ACTIVE MICROWAVE DEVICES .
(Dr.G.KAVYA/PROF/SAEC)
• UNIT-V : MICROWAVE DESIGN PRINCIPLES.
(Dr.M.SELVI/PROF/SCE)

3. AGENDA
• ENGINEERING
• MICROWAVE
• FREQUENCY BANDS
• APPLICATION
• WHY ANTENNA
• WHAT IS ANTENNA
• ANTENNA REGIONS
• ANTENNA PARAMETERS
• FRISS TXN EQUATION

4. ENGINEERING
• PHYSICS(PARTICLE,WAVE)
• ELECTRON (SMALLEST/INVISIBLE/INTERATOMIC NEGATIVELY CHARGED PARTICLE
,ONE MILLIONTH OF THICKNESS OF FIBRE)
• ELECTRON IS A WAVE(SINGLE/RAY/BUNCH)
• ELECTRON OSCILLATION(RADIATION)
• MATHEMATICS(DISTANCE,TIME)
• (TIME-STATIC,DYNAMIC)
• (DISTANCE-INFORMATION)

5. MICROWAVE
• Electronics –Signal ,Communication – EM wave,
• λ = c/f
c-velocity of light(3*100,000 km/sec)(Going around earth-7 and ½ times) ,
f-frequency (Hertz), λ –wavelength (meter).

6. EM FREQUENCY SPECTRUM

7. MICROWAVE FREQUENCY BAND
• Higher the frequency more the bandwidth but shorter coverage area.
• K band is not generally used in communication because it absorbs water vapour in the
atmosphere easily.
• To transmit large volume of data for eg high speed wireless broadband network in an office V
and W band can be preferred.
CONTD…

8. MICROWAVE FREQUENCY BAND
• L band and S band are used for space communication.
• Five satellites of the ISRO including INSAT 3DR sent real time images to the ground station .
• It played key role in saving lives in rain battered Kerala,monitoring the grave flood situation and
assisting in relief work.(Image dated Aug 19,2018).contd

9. MICROWAVE APPLICATIONS
• Microwaves are suitable for Wireless Transmission of signals having larger bandwidth.
• SPACECRAFT (Aircraft safety and mobile navigation to avoid terrain collision , wind shear ).
• MOBILE (Wireless charging of mobile phones using microwaves).contd

10. MICROWAVE APPLICATIONS
• LAW ENFORCEMENT & HIGHWAY SAFETY (Radar speed meters are used by Police for enforcing
speed limit).
• MINE ( Inspection purpose).
• MICROWAVE OVEN (In households for preparation of food).

11. UNIT-1(INTRODUCTION TO MICROWAVE SYSTEMS AND
ANTENNAS)
• ENGINEERING ,MICROWAVE , ANTENNA
• MICROWAVE FREQUENCY BANDS
• ANTENNA REGIONS
ANTENNA PARAMETERS:
• CIRCUIT QUANTITIES
• FIELD QUANTITIES
FRISS TRANSMISSION EQUATION
• LINK BUDGET AND LINK MARGIN

12. WHY ANTENNA
• Short distance (Voice Communication) between two persons is sound waves.
• Long distance (Wireless communication )convert sound waves into EM waves.

13. ANTENNA
• Coordinate system - Address of a point in space .
• Vector - Why? (wind blow)
• Spherical system - Why?

14. ANTENNA
• Point P(r ,θ ,φ ) - (r )radial distance, (θ)-elevation angle( angle between point P and z axis)
,(φ)-azimuthal angle ( angle between projection of point P in xy plane and the x-axis).

15. ANTENNA
• Slicing of lemon fruit.
• Side to side it is cut .
• Top to bottom it is cut.

16. ANTENNA
• Isotropic – Uniform with respect to viewing angle.
• Homogeneous - Uniform with respect to position.(To be the same throughout).

17. ANTENNA – INTERFACE
• EYE – Converts electromagnetic photons into circuit current.
• ANTENNA – Unlike eye interfaces between electrons on conductors with photons in space and
vice versa . It can handle transition in both the directions.(Reciprocity).

18. TRANSMISSION LINE TO ANTENNA

19. WHAT IS ANTENNA
• ANTENNAE or AERIAL
• Transducer(electrical energy into electromagnetic energy and vice versa).
• Transition device between guided wave(plane wave) and free space wave(spherical wave) and vive
versa.
• Conductor which radiates(electrons accelerated and retarded repeatedly),(flow of energy) .
• WEBSTERS dictionary., IEEE Std(metallic tubing device i.e rod or wire for radiating or receiving radio
waves).
• Spatial Filter.( It has the property of being more sensitive to one direction than other which provides
ability to spatially filter signals from its environment).
• Polarization Filter.(It has the property of being more sensitive to one polarization than other which
provides ability to filter signals based on polarization).
• Impedance Transformer.(Intrinsic impedance of free space is (η) E/H =377 Ω).,
(Characteristic impedance of transmission line (ZO) V/I = 50 Ω ) .
• Propagation mode Adapter.(It must serve as a probing device in addition to directional and impedance
transformation device).

20. WAVE PROPAGATION
• SURFACE WAVE - (Ground wave) follows contour of earth .
• SKY WAVE - Signal is reflected from ionized layer of atmosphere back down to earth .
• MICROWAVE -

21. ANTENNA REGIONS
• RNFR -Reactive Near Field Region
• FRESNEL -Radiative Near Field Region (Transition).
• FRAUNHOFER - Radiative Far Field Region .
• L – length of the antenna, λ –wavelength

22. ANTENNA PARAMETERS
• Circuit low frequency- V(V),I (A)
• Field high frequency –E(V/m),H(A/m)

23. PRINCIPAL PATTERN
• The radiation pattern is a graphical (pictorial) ,mathematical representation of the radiation
properties of an antenna as a function of space coordinates. (E/H Plane Patterns)
• Graphically, we surround the antenna by a sphere and evaluate the electric / magnetic fields (far
field radiation fields) at a distance equal to the radius of the sphere.
• For a dipole, this leads to the doughnut pattern in 3D because of the dependence of Eθ on sin θ.

24. RADIATION PATTERN

25. RADIATION PATTERN
• MAJOR LOBE : Radiation lobe containing direction of maximum radiation (main beam).
• MINOR LOBE : Is any lobe except major lobe.
• SIDELOBE : Radiation lobe in any direction other than the intended lobe .
• BACK LOBE : Radiation lobe which makes an angle of approximately 180 degrees with respect
to beam of an antenna

26. RADIATION PATTERN
• HALF POWER BEAMWIDTH : The angular separation between two identical points on opposite
side of pattern maximum . The term beamwidth usually refers to HPBW.
• FIRST NULL BEAMWIDTH : The angular separation between the first nulls of the pattern is
called FNBW.(FNBW).
• The beam width decreases , then side lobe increases and vice versa.
• It describes resolution capabilities ,to distinguish two adjacent sources or targets.

27. ISOTROPIC PATTERN
• It is a hypothetical reference.
• In reality this antenna cannot exist , but is used to compare real antennas with each other . All
real antennas have gain that is compared to this reference.
• The Sun radiates energy equally in all directions.

28. DIRECTIONAL PATTERN
• Designed to be pointed or focused ,in a single direction , somewhat like a flash light .(The light of
the flashlight is strongest at the center of beam and tapers off toward the edges).
• When there is clear LOS from the antenna to the cell tower.
• When all required cell towers are off in the same direction.

29. OMNI DIRECTIONAL
• The 360 degree characteristic of omni antenna similar to light bulb throwing light in all directions
is used in below situations
• They radiate in the horizontal plane.
• When there is no LOS from the antenna to the cell tower.(Areas with mountains or Dense
forests).
• When signal is acquired from cell towers in multiple directions.(Antenna attached to moving car).

30. ISOTROPIC/OMNI DIRECTIONAL/DIRECTIONAL
• The isotropic radiator has got ball(round) shaped radiation.
• Omni directional radiate in the horizontal plane, donot radiate in the vertical plane.
• Directional antenna is focused in a single direction.

31. BEAM SOLID ANGLE
• RADIAN is a measure of plane angle. 1 rad subtends an arc of length r.
• Since the circumference of a circle is 2πr, the number of radians in a complete circle is C/r = 2π
rad.
• STERADIAN is a measure of solid angle. 1 sr subtends a spherical area of area r2 .
• Since a complete sphere has a surface area of 4πr2, there are A/r2 = 4π sr in a sphere.

34. DIRECTIVITY

35. ANTENNA EFFICIENCY

36. ANTENNA GAIN
• The gain of an antenna takes into account the efficiency and directional abilities. But directivity
describes only directional properties controlled by the pattern.
• Defn: measurement of antennas ability to direct or concentrate the radiated signal emitting from
it.(dBi -decibels relative to isotropic radiator)
• Why?-in specification sheet, gain is quoted than directivity because it takes in to account the
actual losses that occur.(Reflection losses,Polarisation losses).

37. EFFECTIVE APERTURE

38. FRISS TRANSMISSION EQUATION