Half-Wave Length Dipole Antenna Design in CST MWS

Antenna Theory: Half-wave length dipole antenna is a type of dipole antenna. This type of antenna is called half wave length dipole antenna because it's length is equal to the half of it's original wavelength. The wave length is always obtained from frequency and these both entities are inversely proportional to each other. The lower the frequency the higher the value of wavelength is, the higher the frequency the lower the value of wavelength is. Therefore we always take a half of that wavelength whenever we need to design a half wave length dipole antenna.

The formula to obtain the length is : lambda=c/f

Where c is speed of light with constant value 3x10*8 m/s and F is frequency of operation which can be in between 30KHz to 300GHz.

Hence to obtain a half wave length of antenna we take: lambda/2

 
Working Principle of Half-Wave dipole antenna:

Advantages 

Disadvantages

Designing of Half Wavelength Dipole Antenna in CST MWS

Step 1. Parameter Calculation

Model Construction: The half wave dipole antenna should operate at 1GHz or 1000 MHz. So you first have to calculate the wavelength from above given formula. The wavelength comes 150 mm. This would be the total length of dipole wire. Moreover the wire must have any diameter so you should take that volume as 5mm. In order to excite the designed antenna you must create gap in above 150mm wire. For gap you need to create 20mm another cylinder of same diameter which can be subtracted from first cylinder. 

Parameter list can be seen in table below.

Fig 1.1 Parameter List

Step 2. Designing 

Now you have calculated the list of parameters you must design that in CST MWS. For that you need to perform following minor steps.

Create new project.

Fig. 2.1 Create New Project

Select Antennas

Fig. 2.2 Select Antennas

Click on Wire 

Fig. 2.3 Select Wire

Select time domain

Fig. 2.4 Select Time domain

Enter frequency range

Fig. 2.5 Enter frequency 

Final Summary

Fig. 2.6 Template Summary

Now you have created a project. It is time to create a cylinder of 150mm length which is aligned with z axis and it is given below.

Fig. 2.7 Cylinder of 150mm length

A cylinder of vacuum needs to be created and inserted in previous shape.

Fig. 2.8 Insert of Vacuum Cylinder

Excitation: a discrete port is used to excite the antenna with impedance of 73 Ohms.

Fig. 2.9 Excitation of half wave dipole antenna

Step 3. Results and Analysis.

Initially the results at the calculated length are observed little bit away from 1GHz. Therefore to shift the resonating frequency you must tweak the length of cylinder. either decrease or increase. The optimal length which has been found by experimenting is 135mm. On this value the resonating frequency will be achieved.

Fig. 3.1 Return Loss 

Step 4. Conclusion

In conclusion the half wave dipole antenna has successfully designed in CST MWS. All of the parameters are calculated and used in software while designing the antenna. All of results were seen to the mark.

Top 5 Frequently Asked Questions of Half Wave Length Dipole Antenna

1. Length of half wave dipole antenna?

Ans. The length of half wave dipole antenna can be found by using formula lambda=c/f , After getting lambda you just need to divide it by two.

2. Half wave dipole antenna applications?

Ans. There are several applications of half wave dipole antenna such as : radio receivers and television receivers.

3. Half wave dipole antenna radiation resistance?

Ans. 73Ohm is the impedance of this antenna.

4. What is half wave length?

Ans. Half wavelength means we get the half of lambda that is obtained from formula which is lambda=c/f, here c is the speed of light and f is the resonant frequency.

5. How do you find the length of half wave dipole antenna?

Ans. It is very easy to find the length just use the formula answered in question 4.

6. What is the gain of half wave dipole antenna?

Ans. As per simulations the maximum gain of half wave dipole antenna can be seen as 2.15 dBi but in reality dipole antenna has higher gain approximately equal to 8dBi.