EC8701 [Updated] AME- ANTENNAS AND MICROWAVE ENGINEERING Lab Viva Short 2 Marks Questions and Answers Free Pdf


EC8701 [Updated] AME- ANTENNAS AND MICROWAVE ENGINEERING Lab Viva Short 2 Marks Questions and Answers Free Pdf

EC8701 [Updated] AME- ANTENNAS AND MICROWAVE ENGINEERING Lab Viva Short 2 Marks Questions and Answers Free Pdf
EC8701 [Updated] AME- ANTENNAS AND MICROWAVE ENGINEERING Lab Viva Short 2 Marks Questions and Answers Free Pdf


Microwave frequency bands, Physical concept of radiation, Near- and far-field regions, Fields and Power Radiated by an Antenna, Antenna Pattern Characteristics, Antenna Gain and Efficiency, Aperture Efficiency and Effective Area, Antenna Noise Temperature and G/T, Impedance matching, Friis transmission equation, Link budget and link margin, Noise Characterization of a microwave receiver.

1. Sketch electromagnetic frequency spectrum showing the location of RF and Microwave frequency bands.

electromagnetic frequency spectrum
electromagnetic frequency spectrum

2. What are microwaves?

Microwaves are electromagnetic waves (EM) with wavelengths ranging from 1mm to 1m. The corresponding frequency range is 300 MHz to 300 GHz

3. List the conditions under which wire radiates.

(i)If charge is moving with a uniform velocity( current created):

a. There is no radiation if the wire is straight, and infinite in extent.

b. There is radiation if the wire is curved, bent, discontinuous, terminated, or truncated.

(ii) If charge is oscillating in a time-motion, it radiates even if the wire is straight.

4. Define reactive near field region of antenna.

Reactive near-field region is defined as “that portion of the near-field region immediately surrounding the antenna wherein the reactive field predominates.” For most antennas, the outer boundary of this region is commonly taken to exist at a distance  R<0.62 √(D 3⁄λ) from the antenna surface, where λ is the wavelength and D is the largest dimension of the antenna

5. Define radiating near field region( Fresnel region) of antenna.

Radiating near-field (Fresnel) region is defined as “that region of the field of an antenna between the reactive near-field region and the far-field region wherein radiation fields predominate and wherein the angular field distribution is dependent upon the distance from the antenna. The inner boundary is taken to be the distance R≥0.62√(D 3⁄λ)and the outer boundary is taken to be the distance R < 2 D2/λ where D is the largest dimension of the antenna.

6. Define far field( Fraunhofer) region of antenna

Far-field (Fraunhofer) region is defined as “that region of the field of an antenna where the angular field distribution is essentially independent of the distance from the antenna. If the antenna has a maximum overall dimension D, the far-field region is commonly taken to exist at distances greater than 2D2/λ from the antenna, λ being the wavelength.

7. A parabolic reflector antenna used for reception with the direct broadcast system (DBS) is 18 inches in diameter and operates at 12.4 GHz. Find the far-field distance for this antenna.

The operating wavelength at 12.4 GHz is λ = c/ f =( 3 × 108)/(12.4 × 109 ) = 2.42 cm. D= 18 inches= 18x0.0254=0.457m The far-field distance is Rff = 2D2 / λ = 2(0.457)2 / 0.0242 = 17.3 m.

8. Define Radiation Intensity. What is it’s significance?

Radiation Intensity in given direction is defined as the power per unit solid angle in that direction.

• The power radiated per unit area in any direction is given by pointing vector P.

• For distant field for which E and H are orthogonal in a plane normal to the radius vector, E2 The power flow per unit area is given by P =   watts/sqm 

• There are r 2 square meters of surface area per unit solid angle( or steradian).

The radiation intensity gives the variation in radiated power versus position around the antenna. We can find the total power radiated by the antenna by integrating the Poynting vector over the surface of a sphere that encloses the antenna. This is equivalent to integrating the radiation intensity over a unit sphere.

9. Define Radiation pattern.

The radiation pattern of an antenna is a plot of the magnitude of the far-zone field strength versus position around the antenna, at a fixed distance from the antenna.

Thus the radiation pattern can be plotted from the pattern function Fθ (θ,φ) or Fφ(θ,φ), versus either the angle θ (for an elevation plane pattern) or the angle φ (for an azimuthal plane pattern). The choice of plotting either Fθ or Fφ is dependent on the polarization of the antenna.

10. Define Half Power Beam Width (HPBW) of an antenna.

Half Power Beam Width is a measure of directivity of an antenna. It is an angular width in degrees, measured on the radiation pattern (main lobe) between points where the radiated power has fallen to half its maximum value.

Half Power Beam Width (HPBW)
Half Power Beam Width (HPBW)

11. Define beam solid angle.

The beam area or beam solid angle ΩA  for antenna is given by integral of the normalized power pattern over a sphere.

12. Define Beam Width between First Null.

Beam width between first null (BWFN) is the angular width in degrees, measured on the radiation pattern between first null points on either side of the main lobe.

Beam width between first null (BWFN)

13. Define main lobe, side lobe, minor lobe and back lobe with reference to antenna radiation pattern.

Major Lobe: Major lobe is also called as main beam and is defined as “the radiation lobe containing the direction of maximum radiation”. In some antennas, there may be more than one major lobe.

Minor lobe: All the lobes except the major lobes are called minor lobe.

Side lobe: A side lobe is adjacent to the main lobe.

Back lobe: Normally refers to a minor lobe that occupies the hemisphere in a direction opposite to that of the major(main) lobe .

Minor lobes normally represents radiation in undesired directions and they should be minimized.

14. Define directivity of an antenna.

The directivity(D) of an antenna is defined as the ratio of the maximum value of the power radiated per unit solid angle to the average power radiated per unit solid angle. That is, directivity is ratio of the maximum radiation intensity in the main beam to the average radiation intensity over all space.

directivity of an antenna

Thus, the directivity measures how intensely the antenna radiates in its preferred direction than an isotropic radiator would when fed with the same total power. Directivity is a dimensionless ratio of power, and is usually expressed in dB as D(dB) = 10 log(D)

15. What do you mean by an isotropic radiator? What is the directivity of isotropic radiator?

An isotropic radiator is a hypothetical loss less radiator having equal radiation in all directions.

isotropic radiator

16. What is the Relationship between Directivity and beamwidth?

Beamwidth and directivity are both measures of the focusing ability of an antenna. An antenna pattern with a narrow main beam will have a high directivity, while a pattern with a wide beam will have a lower directivity.

Approximate relation between beam width and directivity that apply with reasonable accuracy for antennas with pencil beam patterns is the following:

where θ1 and θ2 are the beam widths in two orthogonal planes of the main beam, in degrees. This approximation does not work well for omnidirectional patterns because there is a well-defined main beam in only one plane for such patterns.

17. Define omnidirectional antenna. Give its applications

Antennas having a constant pattern in the azimuthal plane are called omnidirectional, and are useful for applications such as broadcasting or for hand-held wireless devices, where it is desired to transmit or receive equally in all directions.

18. Define pencil beam antenna and give its applications.

Antennas with radiation pattern that have relatively narrow main beams in both planes are known as pencil beam antennas.

Pencil beam antenna are useful in applications such as radar and point-to-point radio links.

19. Define radiation efficiency of antenna.

Radiation efficiency of an antenna is defined as the ratio of the radiated output power to the supplied input power.

Radiation efficiency of an antenna

where Prad is the power radiated by the antenna, Pin is the power supplied to the input of the antenna, and Ploss is the power lost in the antenna(dissipative losses) due to metal conductivity or dielectric loss with in the antenna.

20. Define gain of an antenna. What is the significance of gain of an antenna?/ Relate the gain and directivity of an antenna through proper expression.

The gain of the antenna is closely related to the directivity, it is a measure that takes into account the efficiency of the antenna as well as its directional capabilities. Antenna gain is defined as the product of directivity and efficiency:

gain of the antenna

Thus, gain is always less than or equal to directivity.

21. Define aperture efficiency.

Aperture efficiency is defined as the ratio of the actual directivity of an aperture antenna to the maximum directivity of aperture antenna. The maximum directivity that can be obtained from an electrically large aperture of area A is 

Aperture efficiency

22. Define effective aperture area. What is the relation between effective aperture area and Directivity(gain)?

Received power is proportional to the power density, or Poynting vector, of the incident wave. Since the Poynting vector has dimensions of W/m2, and the received power, Pr, has dimensions of W, the proportionality constant must have units of area.

effective aperture area

where Ae is defined as the effective aperture area of the receive antenna. The effective aperture area has dimensions of m2 , and can be interpreted as the “capture area” of a receive antenna, intercepting part of the incident power density radiated toward the receive antenna. The maximum effective aperture area of an antenna is related to the directivity of the antenna as,

The maximum effective aperture area as defined above does not include the effect of losses in the antenna, which can be accounted for by replacing D with G, the gain, of the antenna

23. Define Antenna Brightness temperature

When the antenna beam width is broad enough that different parts of the antenna pattern see different background temperatures, the effective brightness temperature seen by the antenna can be found by weighting the spatial distribution of background temperature by the pattern function of the antenna.

Mathematically we can write the brightness temperature Tb seen by the antenna as

Antenna Brightness temperature

24. What is the significance of G/T ratio?

Useful figure of merit for receive antennas is the G/T ratio, defined as 10 log( G/ TA) dB/K, where G is the gain of the antenna, and TA is the antenna noise temperature.

This quantity is important because, the signal-to-noise ratio (SNR) at the input to a receiver is proportional to G/TA. The ratio G/T can often be maximized by increasing the gain of the antenna, since this increases the numerator and usually minimizes reception of noise from hot sources at low elevation angles. Of course, higher gain requires a larger and more expensive antenna, and high gain may not be desirable for applications requiring omnidirectional coverage (e.g., cellular telephones or mobile data networks), so often a compromise must be made.

25. State why impedance matching(tuning) is important.

Impedance matching or tuning is important for the following reasons:

(i)Maximum power is delivered when the load is matched to the line (assuming the

generator is matched), and power loss in the feed line is minimized.

(ii)Impedance matching sensitive receiver components (antenna, low-noise amplifier, etc.) may improve the signal-to-noise ratio of the system.

(iii) Impedance matching in a power distribution network (such as an antenna array feed network) may reduce amplitude and phase errors.

26. Give the Friis radio link formula.

Pr= Received power ( antenna matched) in W

Pt= power in to transmitting antenna in W

Aet= Effective aperture of transmitting antenna, m2

Aer= Effective aperture of Receiving antenna , m2

r=distance between transmitting and receiving antenna , m

λ= wave length, m

27. Define EIRP. What is the significance of this quantity?

The product Pt Gt is defined as the Effective Isotropic Radiated Power (EIRP).

EIRP = Pt Gt W

For a given frequency, range, and receiver antenna gain, the received power is proportional to the EIRP of the transmitter and received power can only be increased by increasing the EIRP. This can be done by increasing the transmit power, or the transmit antenna gain, or both.

28. Define path loss.

Path loss is the quantity that account for the free-space reduction in signal strength with distance between the transmitter and receiver.

Path loss= Transmitted power- Received power=Pt - Pr

Assuming unity gain antennas, path loss is given as (using Friis formula)

In practical communications systems it is usually desired to have the received power level greater than the threshold level required for the minimum acceptable quality of service (usually expressed as the minimum carrier-to-noise ratio (CNR), or minimum SNR).

This design allowance for received power is referred to as the link margin, and can be

expressed as the difference between the design value of received power and the minimum threshold value of receive power:

Link margin (dB) = LM = Pr − Pr(min) > 0, where all quantities are in dB.

Link margin should be a positive number; typical values may range from 3 to 20 dB.

Having a reasonable link margin provides a level of robustness to the system to account for variables such as signal fading due to weather, movement of a mobile user, multipath propagation problems, and other unpredictable effects that can degrade system performance.

30. Define fade margin.

Signal fading occur due to weather, movement of a mobile user, multipath propagation problems, and other unpredictable effects that can degrade system performance and quality of service. Link margin that is used to account for fading effects is sometimes referred to as fade margin.

31. How link margin for a given communication system can be improved?

Link margin for a given communication system can be improved by increasing the received power (by increasing transmit power or antenna gains), or by reducing the minimum threshold power (by improving the design of the receiver, changing the modulation method, or by other means)

32. What is point-to-point communication. Mention some of its application.

• In a point-to-point radio system a single transmitter communicates with a single receiver. Such systems generally use high-gain antennas in fixed positions to maximize received power and minimize interference with other radios that may be operating nearby in the same frequency range.

• Point-to-point radios are typically used for satellite communications, dedicated data communications by utility companies, and backhaul connection of cellular base stations to a central switching office.

33. An antenna has a field pattern given by E(θ) = cos2 θ for 0° < θ < π. Find Half Power Beam Width (HPBW).

E(θ) at half power = 0.707.

34. What is Link Budget ? Mention a simple Link Budget equation.

The link budget is a summary of the transmitted power along with all the gains and losses in the communication system and this enables the strength of the received signal to be calculated.

Using this knowledge, it is possible to determine whether power and gain levels are sufficient, too high, or too low and then apply corrective action to ensure the system will operate satisfactorily.



Radiation Mechanisms of Linear Wire and Loop antennas, Aperture antennas, Reflector antennas,Microstrip antennas and Frequency independent antennas, Design considerations and applications.

1. State Huygens Principle

Huygens’ principle states that “each point on a primary wave front can be considered to be a new source of a secondary spherical wave and that a secondary wave front can be constructed as the envelope of these secondary spherical waves .”

2. State Babinet’s principle and how it gives rise to the concept of complementary antenna?

Babinet’s principle states that the sum of the field at a point behind a plane having a screen and the field at the same point when a complimentary screen is substituted, is equal to the field at the point when no screen is present. This principle can be applied to slot antenna analysis.

3. State uniqueness theorem 

Uniqueness theorem states that, for a given set of sources and boundary conditions in a lossy medium, the solution to Maxwell’s equations is unique.

4. What is field equivalence principle?

The field equivalence principle is based on the uniqueness theorem which states that “a field in a lossy region is uniquely specified by the sources within the region plus the tangential components of the electric field over the boundary, or the tangential components of the magnetic field over the boundary, or the former over part of the boundary and the latter over the rest of the boundary .”

5. Draw various types of Horn antenna.

Different types of horn antenna are: E-Plane sectoral horn, H-plane sectoral horn, Pyramidal horn, Conical horn

types of horn antenna

6. Distinguish between sectoral horn and pyramidal horn.

  1. Horn antenna is a wave guide one end of which is flared out. In pyramidal horn, the flaring is along E and H. It has the shape of a truncated pyramid.
  2. In sectoral horn, the flaring is along E or H. If flaring is along the direction of electric field, it is called sectoral E-plane horn. If flaring is along the direction of magnetic field, it is called sectoral H-plane horn.

7. The aperture dimensions of a pyramidal horn are 12x6 cm and operating at a frequency of 10 GHz. Find the beam width and directivity. 

Frequency = 10 GHz

beam width and directivity

8. What are secondary antennas? Give two examples.

Secondary antennas are one that needs a primary antenna to excite it.

Eg: Reflector antenna, Lens antenna.

9. What is a corner reflector?

A corner reflector is made up of two flat-plate reflectors joined together to form a corner. The corner reflector is generally used in conjunction with a dipole or dipole array kept parallel to the corner line. Corner reflector gives a higher directivity.

10. What is the main advantage of Cassegrain reflector configuration?

The main advantage is that the primary feed horn and the associated receiver or transmitter can be located conveniently behind the main reflector.

• The necessity of running long transmission lines or waveguides is also eliminated.

• Since the horn feed is kept behind the main reflector, one can afford to have a much larger aperture for the horn.

11. What is the main disadvantage of Cassegrain reflector configuration?

The main disadvantage of Cassegrain reflector configuration is the large aperture blockage by the sub-reflector. Hence, Cassegrain reflector configuration is used only for very large aperture antennas having gain greater than 40dB.

12. What is slot radiator? What is its operating principle?

When a slot in a large metallic plane is coupled to an R.F source, it behaves like a dipole antenna mounted over a reflecting surface. The slot is coupled to a feed line in such a manner that E-field lies along the short axis of the slot.

13. Write any two differences between slot antenna and its complementary dipole antenna.

  • First, the electric and magnetic fields are interchanged. In case of the dipole antenna the electric lines are horizontal while the magnetic lines form loops in the vertical plane. But in case of slot antenna, the magnetic lines are horizontal and the electric lines are vertical. The electric lines are built up across the narrow dimensions of the slot. As a result, the polarization of the radiation produced by a horizontal slot is vertical and vertical slot is horizontal.
  • Second, the direction of the lines of electric and magnetic force abruptly reverse from one side of the metal sheet to the other. In case of the dipole, the electric lines have the same direction while the magnetic line forms continuous loops.

14. The impedance of an infinitesimally thin λ/2 antenna is 73+j42.5 Ω. Calculate the terminal impedance of an infinitesimally thin λ/2 slot antenna.

15. What is a microstrip antenna?

A microstrip patch antenna is an antenna consisting of a thin metallic patch etched on the dielectric substrate using PCB technology. It is also referred as printed antenna. Its performance depends on shape (can be square, rectangular, triangular, circular) and size.

16. What are the features of microstrip antennas?

  1. Micro strip antennas are low profile, conformable to planar and nonplanar surfaces, simple and inexpensive to manufacture using modern printed-circuit technology, mechanically robust when mounted on rigid surfaces, compatible with MMIC designs, and when the particular patch shape and mode are selected, they are very versatile in terms of resonant frequency, polarization, pattern, and impedance.
  2. In addition, by adding loads between the patch and the ground plane, such as pins and varactor diodes, adaptive elements with variable resonant frequency, impedance, polarization, and pattern can be designed.

17. What are the major operational disadvantages of microstrip antennas?/Point out the limitations of microstrip patch antennas.

Major operational disadvantages of microstrip antennas are their low efficiency, low power, high Q (sometimes in excess of 100), poor polarization purity, poor scan performance, spurious feed radiation and very narrow frequency bandwidth.

18. List the different methods of feeding Microstrip antenna.

(i) microstrip line feed 

(ii) coaxial probe feed

(iii) aperture coupling 

(iv) proximity coupling

19. Define the bandwidth of an antenna.

The band width of antenna is defined as “The range of frequencies within which the performance of the antenna, with respect to some characteristics [input impedance, beam, width, polarization, side lobe level, gain etc.] confirms to a specified standard’’.

20. What is wide band antenna? Give an example.

Antennas which maintain certain required characteristics like gain, front to back ratio, SWR, Polarization, input impedance and radiation pattern over wide range of frequencies are called wide band or broad band antennas. Log periodic antenna is a broadband antenna.

21. State Rumsey principle on frequency independence.

Rumsey’s principle states that the impedance and radiation pattern properties of an antenna will be frequency independent if the antenna shape is specified only in terms of angles.

Example: Planar log spiral antenna.

22. What is LPDA?

LPDA is log periodic dipole array. It is unidirectional broadband, multi element, narrow beam, frequency independent antenna that has impedance and radiation characteristics that are regularly repetitive as a logarithmic function of frequency.

23. Why is log periodic antennas called so?

Log periodic antennas are called so, because, it is an array antenna which has structural geometry such that its impedance and radiation characteristics are periodic with the logarithm of the frequency.

24. Calculate the beam width between first nulls of a 2.5 m paraboloid reflector used at 6 GHz.

25. What is aperture blockage ? Give one example. 

Aperture blockage is the effect of antenna parts lying in the path of rays arriving at or departing from a radiating element or the aperture of an antenna. For example, the feed, subreflector, or support structure may produce aperture blockage for a reflector antenna.

26. Discuss the merits and applications of offset feed reflector antenna.

• Offset feed arrangement, reduce aperture block which reduces the antenna gain.

• It is used as domestic satellite TV receiving antenna



Two-element array, Array factor, Pattern multiplication, uniformly spaced arrays with uniform and non-uniform excitation amplitudes, Smart antennas.

1. What is an antenna array?

2. What is a Linear Array?

3. Define uniform linear array

4. Why we go for non-uniform amplitude distribution?

5. Distinguish between uniform and non-uniform arrays.

6. What is uniform Array?

7. What are the factors that decide the radiation characteristics of array?

8. Define Grating lobes

9. What is end-fire array?

10. Give the condition to have only one end-fire maximum.

11. What is broad-side array?

12. A uniform linear array contains 50 isotropic radiators with an inter element spacing of λ/2 .Find the directivity of broadside forms of arrays. 

13. What is tapering of arrays? 

14. What are the advantages of antenna arrays? 

15. Draw the radiation pattern for a linear array of two isotropic elements spaced λ/2 apart and with equal current fed in phase. 

16. Draw the radiation pattern of an isotropic point sources of same amplitude and opposite phase that are λ/2 apart along X-axis symmetric with respect to origin. 

17. A uniform linear array of 4 isotropic elements with an inter element spacing of λ/2 . Find the BWFN and directivity of end fire arrays.

18. How number of array elements effect directivity?

19. What is the advantage of pattern multiplication?

20. State the principle of pattern multiplication 

21. Using pattern multiplication find the radiation pattern for the broadside array of 4 elements,spacing between each element is λ/2./ Illustrate the pattern multiplication principle.

22. What is the practical major disadvantage of Binomial array?

23. What is the main advantage of Binomial array?

24. What is binomial array?

25. What are the advantages of Dolph-Tschebyscheff array?

26. What is Phased arrays ?

27. Define adaptive array(smart antennas). / Illustrate the features of smart antennas.

28. What is reconfigurable antenna ?



Microwave Passive components: Directional Coupler, Power Divider, Magic Tee, attenuator, resonator, Principles of Microwave Semiconductor Devices: Gunn Diodes, IMPATT diodes Schottky Barrier diodes, PIN diodes, Microwave tubes: Klystron, TWT, Magnetron

1. Define any two performance factors of directional couplers. List out the different types of directional couplers.

2. Name some uses of waveguide Tees. What are the two different types of waveguide Tees?

3. Write the application of magic Tee.

4. What is hybrid ring or Rat-Race junctions?

5. What is negative resistance in Gunn diode? 

6. A Directional coupler is having coupling factor of 20dB and directivity of 40dB. If the incident power is 900mW, what is the coupled power?

7. What are the various materials used for Gunn diodes? What are the four different modes of operation of GUNN diode?

8. Mention the applications of IMPATT diode.

9. What is Gunn Effect?

10. Compare PIN and PN diode.

11. Draw the equivalent circuit of a Gunn diode.

12. List out the different types of Magnetrons.

13. Explain Hull Cut-off condition.

14. What is the purpose of slow wave structures in TWT? Name them.

15. List the advantages of Reflex klystron over multi-cavity klystrons.

16. Explain the need for attenuators in TWT.

17. What is meant by velocity modulation? 

18. Define transit time in a Reflex klystron.

19. Bring out the differences between the TWT & Klystron 

20. What do you meant by bunching?

21. Write the application of Reflex klystron

22. What are the classifications of Microwave tubes and explain the difference between them.

23. Write the application of backward wave oscillator.

24. Define Electronic Admittance.

25. What is drift space?

26. What is magnetron? 

27. What do you mean by O type tube? Name some O type tubes.

28. How to minimize the lead inductance and inter electrode capacitance.

29. Distinguish between O-type and M-type tubes.

30. Give two examples for reciprocal microwave passive device.

31. A Reflex Klystron is operated at 10 GHz with a dc beam voltage of 600 V for 1 3/4 mode, repeller space length of 1 mm and dc beam current of 12 mA. The beam coupling co-efficient is assumed to be 1. Calculate the repeller voltage.

32. A directional coupler is having coupling factor of 20 dB and directivity of 40 dB. If the incident power is 800 mW, what is the coupled power?

33. Specify the scattering matrix of a multi hole directional coupler



Impedance transformation, Impedance Matching, Microwave Filter Design, RF and Microwave Amplifier Design, Microwave Power amplifier Design, Low Noise Amplifier Design, Microwave Mixer Design, Microwave Oscillator Design

1. What do you mean by impedance matching? 

2. Why impedance matching is significant in a microwave system?

3. List out the factors that may be important in the selection of a particular matching network?

4. Define a filter.

5. Write about microwave filter implementation.

6. State the principle behind Richards’ transformation

7. What is the role of Kuroda’s Identities in filter implementation?

8. Sketch Richard’s transformation

9. Sketch the four Kuroda Identities.

10. Mention the significance of Microwave transistor amplifiers.

11. List out the usual microwave amplifier design goals.

12. Define Power gain.

13. Define Available power gain. 

14. Define Transducer power gain. Define transducer power gain of amplifier

15. State the conditions that are necessary and sufficient for unconditional stability.

16. What is the idea behind LNA design?

17. Define noise figure.

18. Give the noise figure expression for a cascaded system.

19. What is role of power amplifiers in transmitters?

20. List out the types and characteristics of power amplifiers.

21. Define a mixer.

22. The IS-54 digital cellular telephone system uses a receive frequency band of 869– 894 MHz, with a first IF frequency of 87 MHz and a channel bandwidth of 30 kHz. What are the two possible ranges for the LO frequency? If the upper LO frequency range is used, determine the image frequency range. Does the image frequency fall within the receive passband?

23. Define conversion loss in a mixer.

24. How are oscillators designed for microwave frequencies?

25. Compare and contrast diode-based and transistor-based oscillators.

26. Why is it necessary to go for microstrip line matching networks?

27. Sketch the frequency response characteristics of ideal Band pass filter and ideal High pass filter.


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