Uploaded March 2026 | Updated September 2026, 1 week ago
Antenna Design playlist. Watch these video to understand more on Antenna Design.
youtube.com/watch?v=RTtCxtSaG8w&list=PLFxhgwM1F4ywAyke2KC22BLBl1V4vV9Jt
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Dipole Antenna Explained: Working Principle, Radiation Pattern, Impedance & Real-World Applications (Animated)
A dipole antenna is one of the simplest and most widely used types of radio antennas. It consists of two conductive elements (usually metal rods or wires) connected to a radio transmitter or receiver. These two parts form a straight line and radiate electromagnetic waves when current flows through them.
Basic Structure
A typical dipole antenna has:
Two equal-length metal conductors
A feed point in the center where the transmission line connects
Each side acts as one “pole” of the antenna (hence the name dipole, meaning two poles)
When radio-frequency current flows into the antenna, it creates an oscillating electric and magnetic field, which radiates outward as radio waves.
Half-Wave Dipole (Most Common Type)
The most common dipole antenna is the half-wave dipole, where the total antenna length is about half the wavelength of the signal being transmitted.
The approximate length is:
𝐿=𝜆/2
or in practical units:
𝐿≈150/𝑓("MHz" ) " meters"
Example:For 100 MHz (FM radio)
𝐿=150/100=1.5m
Each side ≈ 0.75 m
Radiation Pattern
A dipole antenna radiates strongest perpendicular to the wire and weakest at the ends.
Think of the radiation shape like a doughnut around the antenna 🍩
RF Signal is Applied to the Antenna
A radio transmitter sends an alternating current (AC) radio-frequency signal to the antenna through a transmission line (usually a coaxial cable).
The signal enters the center feed point of the dipole antenna.
One side receives positive voltage
The other side receives negative voltage
This creates a time-varying current in the two metal arms.
Current Flows Along the Two Arms
Because the signal is alternating:
Electrons move back and forth along each metal arm.
The direction of current reverses many times per sec (millions of times for radio frequencies).
This movement of charges produces changing electric and magnetic fields around the antenna.
Oscillating Electric and Magnetic Fields Form
Whenever current changes, it creates electromagnetic fields.
Two fields appear:
Electric field (E-field) caused by voltage between the two arms
Magnetic field (H-field) caused by current flowing through the wire
These fields expand outward from the antenna.
Fields Detach and Form Electromagnetic Waves
Close to the antenna the fields are attached to the conductor.
But as the current keeps oscillating:
The electric and magnetic fields start supporting each other
They detach from the antenna
This forms a self-propagating electromagnetic wave that travels through space at the speed of light.
This is the radio signal being transmitted.
Energy Radiates Outward
The radiated energy spreads outward mainly perpendicular to the antenna.
The radiation pattern looks like a doughnut around the antenna.
Maximum radiation → sides of the antenna
Minimum radiation → along the antenna axis
Simple Summary
A dipole antenna works by:
RF current enters the antenna
Electrons oscillate in the two arms
Oscillating electric and magnetic fields form
These fields detach and become electromagnetic waves
Waves radiate into space
Antenna Design playlist. Watch these video to understand more on Antenna Design.
youtube.com/watch?v=RTtCxtSaG8w&list=PLFxhgwM1F4ywAyke2KC22BLBl1V4vV9Jt
For access to this presentation materials, membership is required: I need the Material PPT
Sent me an email to Technologies.Discussion@gmail.com
If you need the whole playlist material, send me email and we discuss.
Give me some time to response. Thanks.
Dipole Antenna Explained: Working Principle, Radiation Pattern, Impedance & Real-World Applications (Animated)
A dipole antenna is one of the simplest and most widely used types of radio antennas. It consists of two conductive elements (usually metal rods or wires) connected to a radio transmitter or receiver. These two parts form a straight line and radiate electromagnetic waves when current flows through them.
Basic Structure
A typical dipole antenna has:
Two equal-length metal conductors
A feed point in the center where the transmission line connects
Each side acts as one “pole” of the antenna (hence the name dipole, meaning two poles)
When radio-frequency current flows into the antenna, it creates an oscillating electric and magnetic field, which radiates outward as radio waves.
Half-Wave Dipole (Most Common Type)
The most common dipole antenna is the half-wave dipole, where the total antenna length is about half the wavelength of the signal being transmitted.
The approximate length is:
𝐿=𝜆/2
or in practical units:
𝐿≈150/𝑓("MHz" ) " meters"
Example:For 100 MHz (FM radio)
𝐿=150/100=1.5m
Each side ≈ 0.75 m
Radiation Pattern
A dipole antenna radiates strongest perpendicular to the wire and weakest at the ends.
Think of the radiation shape like a doughnut around the antenna 🍩
RF Signal is Applied to the Antenna
A radio transmitter sends an alternating current (AC) radio-frequency signal to the antenna through a transmission line (usually a coaxial cable).
The signal enters the center feed point of the dipole antenna.
One side receives positive voltage
The other side receives negative voltage
This creates a time-varying current in the two metal arms.
Current Flows Along the Two Arms
Because the signal is alternating:
Electrons move back and forth along each metal arm.
The direction of current reverses many times per sec (millions of times for radio frequencies).
This movement of charges produces changing electric and magnetic fields around the antenna.
Oscillating Electric and Magnetic Fields Form
Whenever current changes, it creates electromagnetic fields.
Two fields appear:
Electric field (E-field) caused by voltage between the two arms
Magnetic field (H-field) caused by current flowing through the wire
These fields expand outward from the antenna.
Fields Detach and Form Electromagnetic Waves
Close to the antenna the fields are attached to the conductor.
But as the current keeps oscillating:
The electric and magnetic fields start supporting each other
They detach from the antenna
This forms a self-propagating electromagnetic wave that travels through space at the speed of light.
This is the radio signal being transmitted.
Energy Radiates Outward
The radiated energy spreads outward mainly perpendicular to the antenna.
The radiation pattern looks like a doughnut around the antenna.
Maximum radiation → sides of the antenna
Minimum radiation → along the antenna axis
Simple Summary
A dipole antenna works by:
RF current enters the antenna
Electrons oscillate in the two arms
Oscillating electric and magnetic fields form
These fields detach and become electromagnetic waves
Waves radiate into space
