1. Define s-matrix in a microwave junction there is intersection of three or more components.

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There will be an output port, in addition there may be reflection from the junction of other ports. Totally there may be many combinations, these are represented easily using a matrix called S matrix.

2. What are the Properties of s-matrix?

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a. It possess symmetric property sij =sji
b. It possess unitary property [s][s] *=[i]

3.Why is s-matrix used in MW analysis?

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S matrix is used in MW analysis to overcome the problems which occurs when H, Y, & Z parameters are used in high frequencies.
a. Equipment is not readily available to measure total voltage &total current at the ports of the network.
b. Short and open circuits are difficult to achieve over a broad band of frequencies.
c.Active devices, such as power transistor &tunnel diodes, frequently won’t have stability for a short or open circuit.

4.What is a gyroscope?

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• A cluster(N) is a group of cells in which each frequency channel is unique.
• In other words, the N cells which collectively use the complete set of available frequencies is called a cluster.

5. Why is Single stub matching impractical and what is the alternative to it?

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• Single stub matching is sometimes impractical because the stub cannot be placed physically in the ideal location, therefore, double matching is needed and Thus Double stub devices are used.
• Double stub devices consists of two short circuited stubs connected in parallel with a fixed length between them. - The length of the fixed section is usually one-eight, three-eighth, or five-eights of the wavelength.

6.What is co-channel interference?

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Interference between signals from co channels are termed as co channel interference