Tài liệu Transmission line and and waveguide

  • Số trang: 67 |
  • Loại file: PDF |
  • Lượt xem: 261 |
  • Lượt tải: 0
nguyen-thanhbinh

Đã đăng 10809 tài liệu

Mô tả:

1 TRANSMISSION LINES AND WAVEGUIDES Outline 2 1. General Solutions for TEM, TE, and TM Waves 2. Parallel Plate Waveguide 3. Rectangular Waveguide 4. Circular Waveguide 5. Coaxial Line 6. Surface Waves on a Grounded Dielectric Sheet 7. Stripline 8. Microstrip Line 9. The Transverse Resonant Technique 10. Wave Velocities and Dispersion Transmission Line 3 General two – conductor Tx. Closed waveguide General Solutions for TEM, TE and TM Waves 4   Assume time harmonic fields with e-jt dependence and wave propagation along the z-axis. The electric and magnetic field : Transverse components Longitudinal fields components Maxwell Equation 5 Four Transverse Field Components 6  Cut-off wave number  Wave number:  Permittivity of material TEM Wave 7 Transverse electromagnetic (TEM) waves are characterized by: Cut-off wave number : kc = 0 Helmholtz Wave Equation for Ex 8 For dependent, Laplace’s Equation TEM Wave (Cont.) 9 Electric field can be expressed as the gradient of a Scalar potential also satisfies Laplace ‘s equation The voltage and current Wave Impedance 10 Procedure for Analyzing a TEM Line 11 1.Solve Laplace’s equation, for (x, y). The solution will contain several unknown constants 2. Find these constants by applying the boundary conditions for the known voltages on the conductors. 3. Compute 𝑒 and 𝐸 from (3.13) and (3.1a). Compute ℎ and 𝐻from (3.18) and (3.1b). 4. Compute V from (3.15) and I from (3.16). 5. The propagation constant is given by (3.8), and the characteristic impedance is given by Z0 = V/I . TE Wave 12 Transverse electric (TE) waves are characterized by:  Cut-off wave number:  Propagation constant: Helmholtz Wave Equation for Hz 13 TE wave impedance: TM Wave 14 Transverse magnetic (TM) waves are characterized by:  Cut-off wave number:  Propagation constant: Helmholtz Wave Equation for Ez 15 TE wave impedance: Procedure for Analyzing a TE & TM Line 16 1. Solve the reduced Helmholtz equation, (3.21) or (3.25), for hz or ez . The solution will contain several unknown constants and the unknown cutoff wave number, kc. 2. Use (3.19) or (3.23) to find the transverse fields from hz or ez . 3. Apply the boundary conditions to the appropriate field components to find the unknown constants and kc. 4. The propagation constant is given by (3.6) and the wave impedance by (3.22) or (3.26). Attenuation Due to Dielectric Loss 17 Outline 18 1. General Solutions for TEM, TE, and TM Waves 2. Parallel Plate Waveguide 3. Rectangular Waveguide 4. Circular Waveguide 5. Coaxial Line 6. Surface Waves on a Grounded Dielectric Sheet 7. Stripline 8. Microstrip Line 9. The Transverse Resonant Technique 10. Wave Velocities and Dispersion Parallel Plate Waveguide 19  Parallel plate waveguide is the simplest type of waveguide that can support TE, TM and TEM TEM Mode 20 TEM mode solution can be obtained by solving Laplace’s equation: The boundary condition for : There is no variation in x, the solution is:
- Xem thêm -