Interview Questions.

Q1. What Are The Reasons For Using Microwave In Communication?

Wider bandwidth because of better frequency

Better resolution due to smaller wavelength

Higher pace of operation

Higher antenna benefit (length decreasing)

As the production of  frequency in microwave range by means of herbal assets are less , it's far extra to be had and less crowed frequency spectrum. 

Lower interference because of lower sign crowding.

Q2. What Are The Properties Of Microwaves?

Microwave are unidirectional. This me that once an antenna trmits microwaves, they journey in one path. That is why microwave propagation is line of sight (LOS) propagation. They aren't meditated with the aid of ionosphere. High frequency microwaves cannot penetrate an object like wall.

Q3. What Is H-aircraft Tee (shunt Tee)?

An H-plane tee is a waveguide tee in which the axis of its aspect arm is "shunting" the E subject or parallel to the H subject of the primary manual.

Q4. What Is E-aircraft Tee (series Tee)?

An £-plane tee is a waveguide tee wherein the axis of its aspect arm is parallel to the E discipline of the main manual.

Q5. What Is Homo- Junction Tristor?

When the tristor junction is joined via  similar substances such as silicon- to silicon or germanium-to-germanium, it's far called a homo junction tristor.

Q6. What Is Saturated Drift Velocity?

Maximum velocity of rate providers in a semiconductor is referred to as saturation waft pace.

Q7. What Is The Need Of Quality Factor Q?

Quality factor Q that is a measure of the frequency selectivity of a cavity.

Q8. Why Isolator Is Uniline?

An best isolator completely absorbs the power for propagation in a single route and presents lossless trmission in the opposite route. Thus the isolator is normally known as uniline.

Q9. What Is Terminated Line?

A trmission line terminated in its feature impedance Zo is referred to as a well terminated line. Otherwise it is called an improperly terminated line.

Q10. What Is Reflection Loss?

The mirrored image loss is a measure of energy loss for the duration of trmission due to the mirrored image of the signal because of impedance mismatch.

Q11. Write The Applications Of Microwave Engineering?

Following are the applications of microwave engineering:

Antenna gain is proportional to the electric size of the antenna. At higher frequencies, more antenna advantage is therefore viable for a given bodily antenna length, which has vital outcomes for enforcing miniaturized microwave systems.

More bandwidth may be found out at higher frequencies. Bandwidth is critically critical because available frequency bands inside the electromagnetic spectrum are being swiftly depleted.

Microwave alerts journey through line of sight aren't bent with the aid of the ionosphere as are lower frequency alerts and therefore satellite and terrestrial communication hyperlinks with very excessive capacities are viable.

Q12. What Are The Applications Of Microwave?

They are used in several packages. Some of these are:

Communication (astronomy, satellite tv for pc, WLAN, cellular,cellular, radar, TV and so on)

Remote sensing and navigation (prediction/tracking/guidence- traffic manage, weather, missile, plane and many others)

Medical packages (cautery imaging, heart stimulation, therapy etc)

Q13. What Is Hetero Junction Tristor?

When the tristor junction is joined by  different substances inclusive of Ge to GaAs, then it's far known as a homo junction tristor.

Q14. Give Two Examples For Two Port Junctions?

Following are the two examples of two port junctions:

The junction of two square publications of unequal top

A symmetrical junction consisting of  similar square guides joined by means of an Intermediate manual of greater width.

Q15. What Is Power Gain Of An Amplifier?

It is defined as the ratio of electricity brought to the load to that of the strength from the supply into an amplifier.

Q16. What Are Junctions ? Give Some Example?

A microwave circuit includes numerous microwave gadgets related in a few way to obtain the favored trmission of MW signal. The interconnection of two or extra microwave may be appeared as MW junction.

E.G.: TEE, HYBRID RING

Q17. What Is The Need Of Diffusion And Ion Implantation?

Diffusion and ion implantation are the two tactics utilized in controlling amounts of dopants in semiconductor fabrications.

Q18. Why Is S-matrix Used In Mw Analysis?

Matrix is utilized in MW evaluation to conquer the problem which takes place while H,Y & Z parameter are used in excessive frequencies.

Q19. What Is Magic Tees (hybrid Tees)?

A magic tee is a combination of the £-plane tee and H -aircraft tee.  The magic tee is normally used for blending, duplexing, and impedance measurements.

Q20. What Is Wave Propagation In Free Space?

The electromagnetic wave being propagated in unfastened area near the surface of the earth is divided into two elements: 

Ground wave: Classified as direct wave, earth-pondered wave and floor wave

Sky wave or ionosphere wave. 

Q21. Define S-matrix And Its Properties?

In a microwave junction there is an interplay of 3 or more components.There may be an output port, similarly there may be mirrored image from the junction of other ports. Totally there may be many mixture, those are represented effortlessly the usage of a matrix known as S matrix.

Properties of s- matrix:

it possess symmetric houses sij=sji

it possess unitary belongings

[s][s]*=[i]

Q22. What Are Non-reciprocal Devices ?Supply Two Examples?

The devices that are having the homes that the ahead characteristics are not identical to the opposite traits are called non-reciprocal gadgets.

Q23. What Are The Merits And Demerits Of Microwaves?

Due to above houses  microwaves have following blessings and disadvantages:

Due to line of sight propagation, a couple of antennas can be  aligned with out interfering with every other pair of aligned antennas.

Due to huge frequency bandwidth, high information trfer rate is possible.

Due to line of sight propagation, it could be trmitted long distance. But a trouble is faced due to its penetration residences.It can't be trfer internal a bound vicinity. Also its trformation has barriers like hills timber, mountains, earth curvature and so forth. That is why we need repeaters or tall towers for lengthy distance trmission.

As they're now not meditated by ionosphere, they may be used for area trmission.

Q24. What Is Microwave?

Electromagnetic waves having frequencies among 1 GHz to three hundred GHz (it may be 300 MHz to three hundred GHz) are known as microwaves.

Q25. What Are The Properties Of Tem Modes In A Lossless Medium?

Its cutoff frequency is 0.

Its trmission line is a -conductor machine.

Its wave impedance is the impedance in an unbounded dielectric.

Its propagation regular is the regular in an unbounded dielectric.

Its section speed is the speed of light in an unbounded dielectric.

Q26. What Is The Function Of Input And Output Matching Networks?

Input and output matching networks are needed to reduce undesired reflections and enhance the strength float abilities.

Q27. Why Uniform Wave Is A Tem Wave?

A uniform aircraft wave is a wave whose value and section are both consistent. Electromagnetic waves in loose space are standard uniform plane waves. The electric powered and magnetic fields are jointly perpendicular to each other and to the course of propagation of the waves. The stages of the two fields are constantly in time segment and their magnitudes are constantly regular. The stored energies are equally divided among the two fields, and the energy go with the flow is trmitted through the two fields within the path of propagation. Thus a uniform plane wave is a trverse electromagnetic wave or a TEM wave.

Q28. What Is Zero Property Of S Matrix?

It states that, “ for a passive lossless N- port network, the sum of the products of each time period of any row or any column extended by using the complex conjugate of the corresponding phrases of any row or column is 0”.

Q29. What Are Boundary Conditions?

There are four fundamental regulations for boundary situations on the floor between two extraordinary substances:

The tangential components of electrical subject depth are continuous throughout the boundary.

The normal components of electric flux density are discontinuous on the boundary by means of an amount equal to the surface-fee density on the boundary.

The tangential components of magnetic discipline depth are discontinuous on the boundary by means of an amount same to the surface-present day density on the boundary.

The everyday additives of magnetic flux density are continuous across the boundary.

Q30. What Is Non-uniform Wave ?

A non-uniform aircraft wave is a wave whose amplitude (now not phase) may additionally range within a plane ordinary to the path of propagation. Consequently, the electrical and magnetic fields are now not in time segment.

Q31. What Is Hybrid Couplers?

Hybrid couplers are interdigitated microstrip couplers which include 4 parallel striplines with trade strains tied collectively.  Hybrid couplers are frequently used as additives in microwave systems or subsystems such as attenuators, balanced amplifiers, balanced mixers, modulators, discriminators, and phase shifters.

Q32. What Is Microwave Junction?

The factor of interconnection of  or greater microwave gadgets is called a junction. Commonly used microwave junctions encompass such waveguide tees because the E-plane tee, H -aircraft tee, magic tee, hybrid ring (rat-race circuit), directional coupler and the circulator.

Q33. What Is The Purpose Of Slow Wave Structures Used In Twt Amplifiers?

Slow wave systems are special circuits which are used in microwave tubes to lessen wave velocity in a sure direction so that the electron beam and the signal wave can engage. In TWT, for the reason that beam may be improved most effective to velocities which might be approximately a fraction of the rate of light, gradual wave structures are used.

Q34. What Is Insertion Loss?

It is a measure of the lack of the electricity in trmission thru a line or device as compared to the direct shipping of strength without the line or device.

Q35. What Is Unconditional Stability?

It refers back to the situation in which amplifier remains stable for any passive supply and load at the selected frequencies and bias conditions.

Q36. What Is Velocity Of Microwave?

All electromagnetic wave has velocity of light. (Light,microwave,radio wave, infrared ray all are electromagnetic wave).

Q37. What Is Pointing Theorem?

It states that the overall complex energy fed into a volume is equal to the algebraic sum of the lively energy dissipated as warmness, plus the reactive electricity proportional to the distinction between time-average magnetic and electric powered energies saved in the extent, plus the complex power trmitted across the surface enclosed by means of the quantity.

Q38. What Is Trferred Electron Effect?

When GAAs is biased above a threshold cost of the electric subject, it exhibits a negative differential mobility. The electrons inside the decrease strength band may be trferred into the better strength band. This conduct is called trferred electron effect.

Q39. What Is Dominant Mode?

The mode having the lowest resonant frequency.

Q40. What Is Microwave Isolators?

An isolator is a nonreciprocal trmission tool this is used to isolate one factor from reflections of different additives within the trmission line.

Q41. What Are The Applications Of Reflex Klystron?

The major programs of a reflex klystron are as follows:

Signal supply in MW generator

Local oscillators in receivers

It is used in FM oscillator in low energy MW links.

In parametric amplifier as pump supply.

Q42. What Is Available Power Gain?

Available energy gain is described because the electricity available from the microwave community to that of the product from the supply.

Q43. What Is Microwave Engineering?

Microwave engineering is the look at and layout of microwave circuits , components , and structures. Fundamental principles are carried out to evaluation , layout and dimension strategies in this area.The quick wavelengths concerned distinguish this discipline from electronic engineering . This is because there are extraordinary interactions with circuits, trmissions and propagation characteristics at microwave frequencies.

Q44. What Is Tee Junction?

In microwave circuits a waveguide or coaxial-line junction with three unbiased ports is normally known as a tee junction.

Q45. What Are The Advantages Of Abcd Matrix?

The blessings of ABCD matrix are as follows-

They are used in electricity trmission traces

They are beneficial in case of cascade networks.

Q46. What Is Cavity Resonator?

It is a metallic enclosure that confines the electromagnetic energy. Some cavity resonators:  rectangular-hollow space resonator, round-hollow space resonator, and reentrant-hollow space resonator and so on.

Q47. How Does Isolator Increase Frequency Stability ?

Isolators are generally used to enhance the frequency balance of microwave mills, along with klystrons and magnetrons, wherein the mirrored image from the load affects the generating frequency. In such instances, the isolator positioned among the generator and load prevents the contemplated power from the unmatched load from returning to the generator. As a end result, the isolator keeps the frequency balance of the generator.

Q48. What Is Microwave Systems?

A microwave device typically consists of a trmitter subsystem, which include a microwave oscillator, waveguides, and a trmitting antenna, and a receiver subsystem that includes a receiving antenna, trmission line or waveguide, a microwave amplifier, and a receiver.

Q49. What Is Non Reciprocal Devices?

Non reciprocal devices are defined as devices having exceptional forward and reverse propagating traits.

Q50. How To Use Waveguide Corners, Bends, And Twists?

These are generally used to alternate the path of the waveguide through an arbitrary angle.