Microwave cavity 1st 4

Microwave cavity

1. Microwave Cavity By:- Mr. Himanshu Diwakar Assistant Professor JETGI MR. HIMANSHU DIWAKAR CopyRight@JETGI 1

2. Microwave Cavity In general, a cavity resonator is a metallic enclosure that confines the electromagnetic energy . The stored electric and magnetic energies inside the cavity determine its equivalent inductance and capacitance . The energy dissipated by the finite conductivity of the cavity walls determines its equivalent resistance. In practice, 1. The rectangular-cavity resonator, 2. Circular-cavity resonator, 3. And reentrant-cavity resonator Are commonly used in many microwave applications. MR. HIMANSHU DIWAKAR CopyRight@JETGI 2

3. Theoretically a given resonator has an infinite number of resonant modes, and each mode corresponds to a definite resonant frequency. The mode having the lowest resonant frequency is known as the dominant mode . MR. HIMANSHU DIWAKAR CopyRight@JETGI 3

4. Rectangular cavity A microwave cavity acts similarly to a  resonant circuit  with extremely low loss at its  frequency  of operation, resulting in  quality factors  (Q factors) up to the order of 10 6 , compared to 10 2  for circuits made with separate  inductors  and  capacitors  at the same frequency. CopyRight@JETGI 4 Rectangular cavity MR. HIMANSHU DIWAKAR

5. Resonance frequencies of a rectangular microwave cavity for any TE mnl or TM mnl resonant mode can be found by imposing boundary conditions on electromagnetic field expressions . CopyRight@JETGI 5 MR. HIMANSHU DIWAKAR

6. Cylindrical cavity The field solutions of a cylindrical cavity of length L and radius R follow from the solutions of a cylindrical  waveguide  with additional electric boundary conditions at the position of the enclosing plates. CopyRight@JETGI 6 Cylindrical cavity MR. HIMANSHU DIWAKAR

7. Microwave resonant cavities can be represented and thought of as simple  LC circuits .For a microwave cavity, the stored electric energy is equal to the stored magnetic energy at resonance as is the case for a resonant  LC circuit CopyRight@JETGI 7 LC circuit equivalent for microwave resonant cavity MR. HIMANSHU DIWAKAR

8. CopyRight@JETGI 8 Thank you MR. HIMANSHU DIWAKAR