Microstrip antennas have two parts: a metallic patch and a metallic ground plane. The patch can be built in many different geometrical shapes – rectangles, squares, and circles are the most common. They’re becoming increasingly popular in the cellphone industry.
Moreover, the microstrips can be directly printed onto a circuit board – making them highly convenient. The microstrip patch antenna is ideal for use in cellular phones, pagers, missile systems, and satellite communications systems.
If you want to know more about rectangular microstrip patch antennas and how they work, keep reading!
What is A Rectangular Microstrip Patch Antenna?
A rectangular microstrip patch antenna is an antenna that is made up of a rectangular patch. It is a thin square patch on one side of a dielectric substrate with a plane to the ground on the other.
These antennas are a type of planar antenna that has been widely investigated and modified over the last four decades.
In conventional patch antennas, the half-wave dipole is the most basic and extensively used antenna element, consisting of two quarter-wave long linear conductors driven by a source in the middle.
A Rectangular Microstrip Patch Antenna with Edge Feeding is designed to operate at 5.2 GHz frequency.
Significance of Rectangular Patch Antenna
Microstrip patch antennas are used in a variety of wireless applications. Satellite communication, for example, involves circularly polarized radiation patterns, which can be accomplished using either a rectangular or circular patch microstrip antenna.
Circularly polarized microstrip antennae are applied in global positioning satellite (GPS) systems. But they are quite expensive while rectangular patch antennas cost significantly less and provide the same efficiency.
These antennas are also used in the sectors of RFID (radio frequency identification), mobile communication, and healthcare because they are easy to customize.
The wearable application of this antenna is perfect for Wireless Body Area Networks (WBAN).
Types of Rectangular Microstrip Patch Antenna
Microstrip antennas are categorized into several varieties based on their physical properties. The different types of antennas come in a variety of designs and sizes. These antennas are divided into four primary groups, which are as follows:
- Microstrip patch antennas
- Microstrip dipoles
- Printed slot antennas
- Microstrip traveling wave antennas
Widespread application of this antenna can be observed in the medical sector, satellite communication and in many military systems such as rockets, aircraft, missiles, and much more.
Since the substrate material and fabrication are easily accessible, the antennas are frequently used in the commercial aspects too.
Experts predicted that the rising use of rectangular patch antennas in a wide range would overtake the use of conventional ones in the majority of applications.
Structure of Rectangular Patch Antenna
Rectangular microstrip patch antenna is the most often used antenna configuration currently because it is easily installed and constructed on a printed circuit board.
A microstrip patch antenna is a patch made of metal, assisted by a ground plane that is placed on a dielectric substance.
The rectangular patch antenna shape is the most popular and has received the most attention.
Bandwidth of Rectangular Patch Antenna
The microstrip patch antenna still has a restricted bandwidth and low gain efficiency, particularly in a rectangular shape. By single patch, the bandwidth is normally around 2-5% and the gain is 5-7dB.
Designing of Rectangular Patch Antenna
Choosing the feeding method is an important part of designing. There are two ways to feed the antenna: contacting and non-contacting.
The contracting method is more acceptable because it is convenient to model and construct, as well as suit the impedance.
The non-contact method requires connecting an electromagnetic field between the microstrip line and the patch.
Examples of Rectangular Patch Antennas
The rectangular patch is by far the most common. It’s simple to analyze using both the transmission line model and the cavity model, which are the most accurate for this substrate. The arrangement of U and H slots in a rectangular patch is attained by dual and triple frequency operation.
- H-Slot Patch Antenna: H-shaped slots are made by cutting three slots from a rectangular patch, which increases the gain and bandwidth of the microstrip antenna. The ground plane measures (L X W) 90 X 100 mm while the dielectric substrate is 3.2 mm thick. This antenna is circularly polarized and has a single narrow band frequency ratio.
- U-Slot Patch Antenna: A single-band antenna is produced using a simply linked microstrip antenna with a rectangular patch. A single U-slot is carved in the patch for dual-band functioning. The dimensions are (L X W) 32 X 40 mm. The patch substrate thickness is 1.57mm, and the dielectric constant is 4.4. The resonant frequencies are 3.6 and 5.2 GHz.
How Does a Rectangular Patch Antenna Work?
By this point, you might be curious about how this complex device works. However, the antenna works according to some simple principles.
The dielectric material creates waves and reflects them. At the same time, a feeding network activates the microstrip antenna.
As the waves travel to the metal patch’s corners or edges, a fragment of the incident energy is radiated towards the outer area.
Components of a Rectangular Microstrip Patch Antenna
Now, let’s dive into the details of the construction of this invention.
The conducting patches can be found in many different shapes – rectangular, triangular, circular, elliptical, rhombic, hexagonal, pentagonal, and many more. The most frequently used metal patch shapes in microstrip antennas are rectangular or circular.
Since a circular patch antenna takes up less space than a rectangular patch antenna, they are better for array antenna fabrication.
The radiation effects of both circular and rectangular patch antennas remain constant regardless of the shape.
The dielectric material is placed between the ground plane and the metal patch, The dielectric constant can significantly change the antenna performance.
To ensure better implementation, a concentrated dielectric material with a low dielectric constant is recommended in microstrip patch antennas.
Pros and Cons of a Rectangular Microstrip Patch Antenna
Because of the advances in antennas, they are becoming popular day by day. There are numerous advantages of using rectangular patch antennas.
Pros
- Lightweight and Compact: Lightweight, low-cost, low-profile antennas are required for mobile communication. All requirements are met by microstrip patch antennas, and many varieties of microstrip antennas have been devised for use in mobile communication systems.
- Simple fabrication, modification, and personalization: Since the production cost is low, the fabricated antenna may be mass-produced in vast quantities. Furthermore, it’s easily incorporated with Microwave Integrated Circuits (MICs) – making it a very flexible antenna to use. Feed lines and matching networks can be fabricated at the same time.
- Multiple Polarization: It’s capable of both circular and linear polarization. Because the patch antennas are fed along the centerline to ensure symmetry, it reduces the excitation of other harmful modes.
- Bandwidth Enhancement: Easy bandwidth enhancement is achievable by increasing the dielectric material thickness.
- Availability of Diverse Frequency Band: Rectangular microstrip patch antenna can operate at dual and triple frequencies. Changing the frequency range easily is one of the biggest advantages of this antenna. They operate at microwave frequencies where conventional antennas are difficult to design.
Cons:
- Narrow Impedance Bandwidth: The microstrip antenna, in its most basic form, has a narrow impedance bandwidth, often less than 5%. Alternative bandwidth enhancement approaches, however, have been invented.
- Low Power Handling Capacity: The microstrip antenna can withstand relatively low RF power due to the tiny spacing between the radiating patch and its ground plane. The average safe power is a few tens of watts.
- Large Ohmic Loss: While a single patch element has extremely minimal loss because it is just approximately one-half wavelength, microstrip arrays have higher ohmic loss than other forms of antenna arrays of similar aperture size. Due to dielectric and conductor losses, it has low efficiency.
- Low Polarization Purity: It produces more cross-polarization radiation. As a result, achieving polarization purity is difficult. The feeds and other junction points of the microstrip antenna system radiate.
A patch antenna with a thick dielectric substrate and a low dielectric constant will perform well because it will have higher efficiency, a bigger bandwidth, and better radiation.
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Conclusion
In recent years, much research has been conducted on Micro Strip Antennas.
If you compare it to conventional antennas, microstrip patch antennas have more advantages and greater possibilities.
They have agility, broad bandwidth, feedline flexibility, less weight, low volume, cheap cost, low profile, smaller in dimension, and are simple to construct.
Rectangular microstrip patch antennas are truly a wonder in the world of modern technology.