EXPERIMENT-1
AIM: To design a half wave dipole antenna.
SOFTWARE REQUIRED: CST Studio Suite
THEORY:
A dipole antenna is one of the most basic and widely used antenna types in radio frequency (RF)
and microwave communication systems. It is relatively simple in construction and consists of
two conductive elements of equal length, oriented in opposite directions. Dipole antennas are
used for both transmitting and receiving electromagnetic waves, such as radio waves and
microwaves.
A dipole antenna consists of two conductive rods or metals of equal lengths separated by an
insulator.
It is one of the simplest types of antennas and has a 360-degree radiation pattern. The rods are
connected to a wire also called a feeder at the end closest to the center of the antenna. The total
length of the rods is usually one-half of the maximum wavelengths of the signals.
The dipole antenna is cut and bent for effective radiation. The length of total wire, which is being
Used as a dipole, equals half of the wavelength (i.e., L= ƛ/2). Such an antenna is called half -
wave Dipole antenna. This is the most widely used antenna because of its advantages. It is also
known as
Hertz antenna. It is a normal dipole antenna, where the frequency of its operation is half of its
wavelength. Hence, it is called as half - wave dipole antenna.
Figure 1: Plane view of Half wave Dipole Antenna.
The plane view of a half-wave dipole antenna can be seen in Fig. 1. The antenna has a gap
between the two ends for feeding purpose where L is the total length of the antenna, D is the
thickness of the antenna and g is the feeding gap. For a half wave dipole antenna, the radiation
resistance is 73 Ohms which matched the line impedance. The two parts of the antenna are
conductive and can be designed from metal wires.
1. Resonant Frequency (in Hertz)
fr = C/2L
Where
• fr is the resonant frequency
• C is the speed of light in vacuum
• L is the length of each dipole element
2. Length of each dipole element for resonance (for half wave Dipole)
L =C/2fr
3. Input Impedance (for half wave Dipole in free space)
Zin = 73 + j42.5
The input impedance of a dipole antenna is approximately 7352 resistive with a
reactive component.
The dimension of the designed antenna.
Parameter Value Unit
Resonant Frequency(fr) 4 GHz
Feed Gap (Fg) 0.75 mm
Impedance (z) 73 Ohms
Length of dipole antenna (L) 37.5 mm
Radius of dipole antenna (R) 1.5 mm
OBSERVATION:
S-parameter
Electric field
Magnetic Field
Surface Current
Radiation Pattern
RESULT: Dipole antenna has been designed and simulated.
