An antenna converts electric power to radio waves and vice versa. It is usually used with a radio transmitter or receiver. There are several types of antennas including wire antennas, traveling wave antennas, reflector antennas, microstrip antennas, log-periodic antennas, and aperture antennas. A patch antenna is a type of radio antenna that is low profile and can be mounted on a flat surface. It consists of a flat metal patch mounted over a larger ground plane. Patch antennas are widely used today in applications like satellite communication, GPS, and mobile devices due to their compact size and light weight.

1. Antenna
An antenna or aerial, is an electrical device which converts electric power
into radio waves, and vice versa. An antenna is a conductor that can
transmit, send and receive signals such as microwave, radio or satellite
signals. It is usually used with a radio transmitter or radio receiver.
Figure: Some common features of antenna.

2. Classification
•Wire Antennas
Wire Antennas
Short Dipole Antenna
Dipole Antenna
Half-Wave Dipole
Broadband Dipoles
Monopole Antenna
Folded Dipole Antenna
Loop Antenna
Cloverleaf Antenna

3. •Travelling Wave Antennas
 Helical Antennas
Yagi-Uda Antennas
Spiral Antennas
•Reflector Antennas
Corner Reflector
Parabolic Reflector (Dish Antenna)

4. •Microstrip Antennas
Rectangular Microstrip (Patch) Antennas
Planar Inverted-F Antennas (PIFA)
•Log-Periodic Antennas
Bow Tie Antennas
Log-Periodic Antennas
Log-Periodic Dipole Array

5. •Aperture Antennas
Slot Antenna
Cavity-Backed Slot Antenna
Inverted-F Antenna
Slotted Waveguide Antenna
Horn Antenna
Vivaldi Antenna
Telescopes
•Other Antennas
NFC Antennas
Fractal Antennas
Wearable Antennas

6. Patch antenna
A patch antenna (also known as a rectangular micro strip antenna) is a
type of radio antenna with a low profile, which can be mounted on a flat
surface. It consists of a flat rectangular sheet or "patch" of metal,
mounted over a larger sheet of metal called a ground plane.
Figure: Microstrip Patch Antenna

7. Multiband Antenna
An antenna designed to operate on several bands. These antennas often
use designs where one part of the antenna is active for one band, and
another part is active for a different band. A multiband antenna may
have lower than average gain or may be physically larger in
compensation.
Figure: Multiband Antenna

8. Patch antenna length and wide equation

9. Dielectric substrate
• Microstrip is a type of electrical transmission line which can be
fabricated using printed circuit board technology, and is used to
convey microwave-frequency signals. It consists of a conducting strip
separated from a ground plane by a dielectric layer known as the
substrate.

10. Applications of Patch antenna
Microstrip Patch antennas are widely used in today’s era. It is widely
used due to its compact shape and light weight, les complexity and easy
to implement. Some widely usage fields of patch antenna are
mentioned blown are :
 satellite communication
 military purposes
 GPS
 mobile
 missile systems
 Navigational System
 Non satellite based application such
as medical hyperthermia
 Integrated phased array system
 Direct broadcast satellite system and
remote sensing

11. Frequency allocation
Use of radio frequency bands of the electromagnetic spectrum is regulated
by governments in most countries, in a Spectrum management process
known as frequency allocation or spectrum allocation.
Figure: Example of frequency allocation table
( United States)

12. Advantage or disadvantage of patch
antenna
• Advantages:
 Ease of manufacturing
 It has a very low fabrication cost.
 Microstrip patch antennas are efficient radiators.
 It has a support for both linear and circular polarization.
 Easy in integration with microwave integration circuits.

13. • Disadvantages:
 Low impedance bandwidth.
 Low gain.
 Extra radiation occurs from its feeds and junctions.
 Excitation of surface waves.
 Size of micro strip antenna comes in both advantages and
disadvantages but there are some applications where the size of
microstrip antenna is too large to be used.