Antenna Design, Monopole Antenna

IIIa. Laboratory

Problem Set 1. A half-wave dipole in free space

CST filename: half-wave-dipole.cst

Wire end-to-end length (including the feed gap) = 182

Wire diameter = 4

Feed gap = 2

Frequency range: 400-1200 MHz

Field monitor: Farfield at the resonant frequency of the antenna. This will be done after S11 is calculated. 

P1. Draw the antenna geometry.

P2. Plot |S11| (dB) and add an 'Axis Marker' to find the frequency for minimum |S11| (dB). Remove the 'Axis Marker' and add 'Measure Lines' at |S11| (dB) = -10 dB.

Center frequency = ( ) MHz

Bandwidth = ( ) MHz

P3. Plot Rin and Xin on a same graph with 'Axis Marker' at Xin = 0. Find the resonant frequency (for Xin =0) and the resonant resistance (for Xin = 0). Express the dipole length in the resonant wavelength.

     Resonant frequency = ( ) MHz

     Resonant resistance = ( ) ohms

Dipole length in wavelength: wavelength = 300/0.751 = 399, Dipole length = 182/399 = 0.456 wavelength

P4. Plot Gtheta in 3D at resonant frequency and find the maximum gain.

Gmax = ( ) dBi

Problem Set 2. A quarter-wave monopole on an infinite ground plane

CST filename: quarter-wave-monopole.cst

Wire length (except the feed gap) = 90

Wire diameter = 4

Feed gap = 1

Frequency range: 400-1200 MHz

Field monitor: Farfield at the resonant frequency of the antenna. This will be done after S11 is calculated. 

P5. Make the antenna geometry and plot it in 3D.

P6. Plot |S11| (dB) and add an 'Axis Marker' to find the frequency for minimum |S11| (dB). Remove the 'Axis Marker' and add 'Measure Lines' at |S11| (dB) = -10 dB.

Center frequency = ( ) MHz

Bandwidth = ( ) MHz

P7. Plot Rin and Xin on a same graph with 'Axis Marker' at Xin = 0. Find the resonant frequency (for Xin =0) and the resonant resistance (for Xin = 0). Express the dipole length in the resonant wavelength.

     Resonant frequency = ( ) MHz

     Resonant resistance = ( ) ohms

Dipole length in wavelength: wavelength = 300/0.76 = 395, Monopole length = 91/395 = 0.230 wavelength

P8. Plot Gtheta in 3D at the resonant frequency and find the maximum gain.

Gmax = ( ) dBi

Problem Set 3. An inverted L antenna on an infinite ground plane

CST filename: ILA.cst

Wire length: vertical H = 30, horizontal L = 60

Wire diameter d = 4

Feed gap g = 1

Frequency range: 400-1200 MHz

Field monitor: Farfield at the resonant frequency of the antenna. This will be done after S11 is calculated. 

P9. Make the antenna geometry and plot it in 3D.

P10. Plot |S11| (dB).

P11. Plot Rin and Xin on a same graph with 'Axis Marker' at Xin = 0. Find the resonant frequency (for Xin =0) and the resonant resistance (for Xin = 0).

     Resonant frequency = ( ) MHz

     Resonant resistance = ( ) ohms

P12. Plot Gtheta in 3D at the resonant frequency and find the maximum gain.

Gmax = ( ) dBi

Problem Set 4. An inverted F antenna on an infinite ground plane

CST filename: IFA.cst

Wire length: vertical H = 30, horizontal L = 60

Wire diameter d = 4

Feed gap g = 1

Shorted-wire to feed-wire gap S = 1, 3, 5, 7 (Use the parameter sweep)

Frequency range: 400-1200 MHz

Field monitor: None

P13. Draw the antenna geometry.

P14. Plot |S11| (dB) for four cases on a same graph.