microwave component

STUDY OF MICROWAVE COMPONENTS

AIM: To Study about Microwave Components.

THEORY: REFLEX KLYSTRON:

It is composed of heater, cathode, focusing electrodes and repeller anode. All these components are enclosed in a glass envelope. After the focusing electrodes there is a cavity resonator which encircles the glass envelope. A loop coupling is used inside the cavity to get the output.

GUNN OSCILLATOR:

Gunn Oscillators are used to generate the microwave signal and its Micrometre is used to tune the output frequency of Gunn oscillator.

WAVEGUIDE TWIST:

Waveguide Twist is used to change the plane of Polarization of a wave Guide transmission line. Twist is made from a section of waveguide which has been precisely twisted. 900 twists is a standard available model.

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LAB MANUAL EC P71-COMMUNICATION LABORATORY - III

MATCHED TERMINATION:

Matched terminations are used to terminate the waveguide transmission line operating at low average power. The loads are carefully designed to absorb all the applied power and VSWR of matched termination is low. These are used in the measurement of reflection coefficient and where the matched load is required.

MOVABLE SHORTS:

Movable Short is a sophisticated equipment, normally utilized in different experiments to study the characteristics of reflex klystron and frequency, guide wavelength and free space wave length. Our equipment, manufactured and supplied in different configurations, are preferred for their accurate and smooth performance. They are also credited for better operational life and sturdiness.Advantages:

Corrosion resistant Easy installation Capable of withstanding extreme pressure Competitive pricing

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PRECISION MOVABLE SHORT:

Movable shorts are used to obtain a phase reference in the calibration of various experimental setups .These are also used to vary the effective plane of reflection and therefore the phase of reflected wave. Movable shorts are used to measure the impedance of a device. Movable shorts are of two types one has no provision to record position of short in the waveguide and other type of movable short is precision movable short in which position of short can be accurately recorded from micrometre.Advantages

Sturdy structure Low maintenance Easy installation Capable of withstanding extreme conditions

PHASE SHIFTER:

Many applications require phase shift to be introduced between two given position in a waveguide system. It consists of a dielectric slab or vane specially shaped to minimize reflection effect. Phase shifter are used to change the effective electrical length of transmission line without changing its physical length. They are particularly useful in microwave bridge circuit where the phase and amplitude must be adjusted independently.

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TUNABLE PROBE:

Tunable probes are very useful devices to measure the SWR and Impedances. Tuneable probe is consists of a crystal detector and a small wire antenna in coaxial housing. Its depth of penetration into the slotted section is variable.

SLIDE SCREW TUNERS:

Slide Screw Tuner is a very useful component in a microwave laboratory. It is mainly used for Impedance measurement. Its tuner can be adjusted for low and high impedance position.

KLYSTRON MOUNT:

Klystron mounts are used to transmit microwave power from reflex klystron tube to rectangular waveguide. Klystron mounts are designed by a section of waveguide, one end of waveguide is fitted with a movable short plunger. A small hole on the broad wall of

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waveguide is provided through which coupling pin of reflex klystron tube enters into the waveguide. By moving plunger (matching the impedance of klystron tube and waveguide) maximum output can be achieved.

PIN MODULATOR:

Pin diode modulators are used to provide amplitude or pulse modulation in wide range of microwave to study many applications. These modulators uses PIN diode which is mounted across the waveguide line with RF isolated DC bias lead passing to an external TNC (F).

DIRECT READING FREQUENCY METER:

Direct Reading frequency meters are used to measure the microwave frequency accurately. There long scale length and numbered calibration marks provide high resolution which is particularly useful when measuring frequency difference of small frequency changes.

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Wave Guide Adaptor:

Adaptors transform waveguide impedance to coaxial impedance. Adopters consist of a short section of waveguide with a probe transition mounted on broad wall. Power can be transmitted in either direction. Each adaptor covers the 50% of the waveguide.

FIXED ATTENUATORS:

Attenuators are required to adjust power or attenuate the power flowing in waveguide. There are two type of attenuators fixed and variable. Fixed attenuators available in various range like 3dB, 6dB, 10dB etc. These attenuators are calibrated at centre frequency of respective frequency band. By Variable attenuators power can be adjusted for different level.

High attenuation precision Excellent stability Excellent reliability.

Variable Attenuator:

We have gained expertise in delivering a quality range of Variable Attenuator 20db. The offered range of variable attenuator 20 db is available in different customized forms and models in accordance with the varied demands of the valued clients. This range of variable attenuators is developed using superior grade components and advanced machinery, in adherence with the industry laid standards and guidelines. Features:

Compact size Light weight

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Rugged construction.Attenuator is design by two type:1. Active design

a. Narrowband active variable attenuatorb. Broadband active variable attenuator

2. Passive designa. Pi attenuatorb. Tee attenuatorc. Bridge T attenuator

E-PLANE BENDS:

In measurements it is often necessary to bend a waveguide by some angle. Waveguide bends in E and H plane of 90° is normally available. Waveguide bends designed by a section of rectangular waveguide and flange.

H PLANE BENDS:

Waveguide is normally rigid, except for flexible waveguide, and therefore it is often necessary to direct the waveguide in a particular direction. Using waveguide bends it is possible to arrange the waveguide into the positions required. When using waveguide bends it is necessary to ensure the bending is accomplished in the correct manner otherwise the

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electric and magnetic fields will be unduly distorted and the signal will not propagate in the manner required causing loss and reflections. Accordingly waveguide bend sections are manufactured specifically to allow the waveguide direction to be altered without unduly destroying the field patterns and introducing loss.

MULTI HOLE DIRECTIONAL COUPLER:

Directional coupler are designed to measure incident and reflected power values and also provide a signal path to a receiver or perform other desirable operation. In its most common form, the directional coupler is a four fort waveguide junction consisting of a primary main waveguide and a secondary auxiliary waveguide. These are available in 3, 6, 10, 20, 40 dB coupling.

CROSS DIRECTIONAL COUPLER:

Cross Directional Coupler consists of two waveguide sectional joint at (90°) with the coupling element mounted into the common broad wall.

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SOLID DIELECTRICAL CELL:

These are used to measure dielectric constant of any solid material these consists of a cavity for keeping the sample and micrometre to read the position of sample. Solid Dielectric cell consists of a section of waveguide flanged on both ends and one end is terminated with a polished fixed reflector. These are meant for measurement of dielectric constant of solids.

SHORTING PLATE X BAND:

Being a client-centric organization, we are engaged in offering a comprehensive and wide range of Fixed Waveguide Shorts. These products are highly demanded in the market, owing to their salient features like high tensile strength, longer life and corrosion resistance. Manufactured using sophisticated technology, this range is offered in several specifications as per the diverse requirements of the customers.Features:

Highly compact size User friendly Low maintenance cost.

LIQUID DIELECTRICAL CELL:

These are used to measure dielectric constant of any solid material these consists of a cavity for keeping the sample and micrometre to read the position of sample.

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TEE:

Tees are used to combine power from two input or divided the microwave power from one input to two output lines. Tee is an intersection of three waveguides in the form of alphabet T.E PLANE TEE:

As shown in figure is an E-plane Tee junction, as it is an intersection of three waveguides in the form of alphabet T. Port 1 and 2 are collinear arms while port 3 is the E arm, which is along the broader dimensions of waveguides. The T junction is used for power division or power combining.

H PLANE TEE:

An H-type T-junction is illustrated in the beside figure. It is called an H-type T-junction because the long axis of the “B” arm is parallel to the plane of the magnetic lines of force in the waveguide. The E field is fed into arm A and in-phase outputs are obtained from the B and C arms. The reverse is also true. H plane tee is so called because the axis of the side arm is parallel to the planes of the main transmission line. As all three arms of the H plane tee lie in the magnetic field, the magnetic field divides itself into the arms. Therefore this is also called a CURRENT JUNCTION.

MAGIC TEE /E-H TEE:

A magic tee is a combination of E-plane and H-plane Tee. Magic tee, combines the power dividing properties of both H-plane and E-plane tee, and has the advantages of being completely matched at all the ports. If two signals of same magnitude and phase are fed into port 1 and port 2, then output will be zero at port 3 and additive at port 4. If signal is fed from

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port 4 (H-arm) then signals divides equally in magnitude and phase between port 1 and 2 and no signal appears at port 3 (E-arm). If signal is fed into port 3, then signal divides equally in magnitude, but opposite in phase at port 1 and 2, and no signal comes out from port 4, i.e. output at port 4 is zero.

WAVE GUIDE DETECTOR MOUNT:

The crystal detector can be used for the detection of microwave signal. At low level of microwave power, the response of each detector approximates to square law characteristics and may be used with a high gain selective amplifier having a square law meter calibration.

FERRITE ISOLATOR, T CIRCULATOR, Y CIRCULATOR:

The ferrites isolators and circulators are matched 2 port and 3 port devices respectively, which offer low insertion loss and high isolation over 1GHz band width. An isolator is a 2 port device which allows signals from port 1 to port 2 & provides maximum attenuation for transmission from port 2 to 1. A circulator is a three port device which has a peculiar property of coupling power to the adjacent port clockwise.A circulator is a ferrite device with usually three ports. They are non-reciprocal. That is, energy into port 1 predominantly exits port 2, energy into port 2 exits port 3 and energy into port 3 exits port 1. In a reciprocal device the same fraction of energy that flows from port 1 to port 2 would occur to energy flowing the opposite direction, from port 2 to port 1.

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MICROMETRE TYPE FREQUENCY METER:

Micrometre type frequency meters are consists of a microwave cavity with plunger and a section of waveguide. It consists of a micrometre to measure its position for measuring frequency.

WAVEGUIDE ANTENNAS:

There are several types of microwave antennas like standard Gain, Pyramidal horn, Pick up horn, Dielectric antenna, Parabolic dish antenna etc. these are used to radiate microwave energy in the air and to receive the energy from air.

SLOTTED SECTION:

Slotted section is used to measure various measuring parameter in microwave. For example to determine VSWR, phase and impedances. These consist of a slot in centre of waveguide in which we can connect a probe and probe can be moved in slot and position of probe can be

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measured by its Vanier scale. The travel of probe carriage is more than three times of half wavelength.

GUNN POWER SUPPLY:

Gunn power supply comprises of an electronically regulated DC power supply and a square wave generator designed to operate Gunn oscillator and pin modulator simultaneously. The DC voltage is variable from 0 to 10 volts. The frequency of square wave can be continuously varied from 800 to 1200 Hz. The front panel meter can read the Gunn voltage and the current drawn by the Gunn diode. The power supply is designed to protect Gunn diode from reverse voltage application from over voltage transients and from low frequency oscillations.

KLYSTRON POWER SUPPLY:

Klystron Power Supply, is a state-of the-art solid-state, regulated power supply for operating low power Klystrons such as 2K25. It incorporates a number of proprietary features:1. Regulated Beam Supply and Repeller Supply voltages.2. LED Digital metering for Beam voltage, current and Repeller voltage.3. Compact and Reliable.4. Modular construction for easy maintenance.In addition to AM and FM modulation of Beam current, a provision for externally modulating the Klystron supply with desired signal waveform has been provided. Klystron Power supply utilizes the quality components and rugged construction. A careful handling of the instrument will provide years of trouble free service. The equipment is divided in two parts one is high voltage unit and other is modulation unit. It makes it user friendly.

SWR METER:

The model SWR meter is a high gain low noise, tuned voltmeter operating at fixed frequency. It is designed for making standing wave measurement in conjunction with a suitable detector and slotted line or wave guide section. It may be used as null detector in bridge circuit and as fixed frequency indicator. It is calibrated to indicate directly SWR or db when used with square law devices such as crystal diode. It has expanded scales for accurate reading of small increments. It is adjusted for operation at 980Hz to 1020 Hz to avoid harmonics of the line frequency.RESULT: Thus the microwave components were studied.

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microwave component

Documents

movable shorts

type of movable short

position of short

waveguide twist

waveguide transmission

section of waveguide

phase reference

microwave laboratory