DEPARTMENT OF ELECTRONICS AND COMMUNICATION
EXP 1 - .STUDY OF MICROWAVE SYSTEM AND COMPONENTS
To study the Microwave system and components.
A Microwave system normally consists of Transmitter subsystems including a microwave oscillator wave guide and a terminating antenna and a receiver subsystem that includes a receiving antenna transmission line or wave guides, A microwave amplifier and a receiver .
WAVE GUIDE TEES:
Wave guide Tees may consists of the E-Plane Tee, H-Plane Tee, magic Tee, Hybrid rings, Comers bend and Twists.
E-Plane Tee: (Series Tee)
An E-Plane Tee is a waveguide lies in which the axis of its side arm is parallel to the E Field of the main guide as shown in figure. When the waves are fed into the side arm(port3) the waves appearing at port1 and port2 of the collinear arm will be in opposite phase and to same magnitude.
H-Plane Tee(Shunt Tee):
A H-Plane Tee in a wave guide Tee in which the axis of its side arm is shunting the E-Field or Parallel to the H-Field of the main guide as shown in figure. It can be seen that if two input waves are fed into port1 and port2 of the collinear arm, The output wave at port2 the wave split equally into port1 and port2 in phase and in same magnitude.
Magic Tee(Hybrid Tee):
A Magic Tee is a combination of the E-plane Tee and H-Plane Tee. The magic Tee has several characteristics: 1. If two waves of equal magnitudes and the same phases are fed into port1 and port 2, the output will be zero at port3 and at port4. 2. If a wave is fed into port4(the H-arm) it will be divided equally between port1 and port2 of the collinear arm and will not appear at port3(E-arm). 3. If a wave is fed into port3 (the E-arm) it will produce an output of equal magnitude and opposite phase at port1 and port2 and the output at port4 is zero. 4. If a wave is fed into one of the collinear arms at port1 and port2, it will not appear in the other collinear arm at port2 or port1 because the E-arm causes the phase delay while the H-arm causes a phase advance.
A Directional coupler is a 4 port wave guide junction as shown in fig. It consists of a primary wave guide 1-2 and secondary wave guide 3-4 when all ports are terminated in their characteristics impedance; there is a free transmission of power with out reflection between port1 and port3 or between port2 and port4. Because no coupling exists between port1 and port4. And between port2 and port3 depends upon the structure of the coupler.
The characteristics of the directional coupler can be expressed in terms of its coupling factors and its directivity. Assuming that the wave is propagating from port1 and port2 in the primary line the coupling factors and directivity are defined by
Coupling factors (dB) = 10 log10 (P1 /P4)
Directivity (dB) = 10 log10 (P4 /P3)
Where P1 – Power input to port1
P3- Power output from port2
P4- Power output from port4.
THE DIRECTIONAL COUPLER:
Microwave circulator is a multiport wave guides junction in which the wave can flow only from nth port to the (n+1) th port in one direction. Although there is no restriction on the number of ports, the 4 port microwave circulator is the most common.
Isolator is a non reciprocal transmission device that is used to isolate one component from reflections...