Skip to main content

Microstrip Path Antenna Introduction

Key Takeaways

  • Microstrip patch antennas are compact, low-profile antennas widely used in wireless communication systems due to their ease of integration into devices.

  • Their construction involves key components such as the radiating patch, dielectric substrate, ground plane, and feeding mechanism.

  • Microstrip patch antennas offer benefits such as compact size, low profile, directional radiation, and cost-effectiveness, but have drawbacks like lower efficiency, cross-polarization radiation, and limited power handling capability.

Microstrip patch antenna construction summary

Microstrip patch antenna construction summary

In the world of wireless communication, microstrip patch antennas have emerged as a popular choice due to their compact size, low profile, and ease of integration into various devices. These antennas offer a range of benefits that make them ideal for a wide array of applications, from mobile phones and wireless routers to satellite communication systems and radar technology. Read on as we explore what microstrip patch antennas are, their construction, and the benefits and use cases that make them a valuable component in modern wireless communication systems.

What Is a Microstrip Patch Antenna?

A microstrip patch antenna is a type of antenna that operates in the microwave frequency range. They can be printed directly onto circuit boards and are low-profile. They consist of a radiating patch, usually made of conductive material, mounted on a dielectric substrate.

The patch is typically fed by a transmission line, which provides the necessary RF signals to generate electromagnetic waves. The patch and the substrate together form a planar structure, making microstrip patch antennas flat and lightweight. Their compact design and ease of fabrication make them highly desirable for applications where space and weight are critical factors.

By adjusting the dimensions of the radiating patch and the substrate properties, microstrip patch antennas can be tailored to operate at specific frequencies within the microwave range. This flexibility allows for the customization of antennas to meet the requirements of different wireless communication systems and applications.

Microstrip Patch Antenna Key Components

Radiating Patch

The radiating patch is the most crucial element of the antenna. It is typically made of a conductive material, such as copper or gold, and shaped in a specific geometric pattern. Common patch shapes include square, rectangular, circular, or elliptical. The dimensions of the patch, including its length, width, and shape, determine the operating frequency and radiation characteristics of the antenna.

Dielectric Substrate

The radiating patch is mounted on a dielectric substrate, which provides mechanical support and electrical insulation. The substrate is typically made of low-loss materials with a high dielectric constant, such as fiberglass-reinforced epoxy or ceramic. The choice of substrate material affects the antenna's performance, bandwidth, and efficiency.

Ground Plane

Beneath the substrate lies a conductive ground plane. It acts as a reflector and improves the antenna's radiation efficiency by providing a return path for the electromagnetic waves. The ground plane is usually larger than the radiating patch to reduce radiation losses.

Feeding Mechanism/ Transmission Line

The radiating patch is fed by a transmission line, typically in the form of a microstrip or coaxial cable. The feeding mechanism connects the patch to the RF signal source and determines the polarization and radiation pattern of the antenna.

Square Microstrip Patch Antenna Center Frequency

The microstrip antenna illustrated in the figure above is fed by a microstrip transmission line. 

The patch has specific dimensions, including length L and a width W. It is positioned on top of a substrate, which is a dielectric circuit board, with a thickness H and a permittivity as εr. 

The thickness of either the ground plane nor the microstrip significantly affects the center frequency. In general, the thickness is much smaller smaller than the operating wavelength, but not  any less than 0.025 times the wavelength (equivalent to 1/40th of a wavelength) to avoid degradation of antenna efficiency. The center frequency of the microstrip path antenna can then be approximated as: 

Square Microstrip Patch Antenna Center Frequency

Patch Antenna Benefits

Microstrip patch antennas offer several advantages that make them widely used in various wireless communication systems. Here are some key benefits and use cases:

  • Compact Size: The small form factor of microstrip patch antennas allows them to be easily integrated into portable devices like smartphones, tablets, and smartwatches.
  • Low Profile: Microstrip patch antennas have a low profile and can be mounted on flat surfaces. 
  • Directional Radiation: Microstrip patch antennas can be designed to have a directional radiation pattern, focusing the emitted energy in a specific direction. This characteristic is beneficial for applications like point-to-point communication links and radar systems, where a well-defined beam is desired.
  • Cost-Effective: The fabrication process for microstrip patch antennas is relatively simple and cost-effective compared to other types of antennas. 
  • Microstrip patch antennas have a wide variety of use cases, including aircraft, spacecraft, mobile radio, and wireless communications

Microstrip Patch Antenna Drawbacks

One of the drawbacks of a microstrip patch antenna is its low efficiency, which can be attributed to both dielectric losses and conductor losses. As a result, the antenna may exhibit lower gain compared to other types of antennas. Additionally, microstrip patch antennas tend to have a higher level of cross-polarization radiation, which can affect the quality of the transmitted or received signals. Another limitation is their lower power handling capability, which means they may not be suitable for applications that require high power transmission.

Ready to design and optimize microstrip patch antennas for your wireless communication systems? Explore the capabilities of Cadence AWR software, a powerful tool that simplifies antenna design, simulation, and analysis. Enhance your antenna performance and achieve optimal results. Get started today!

Leading electronics providers rely on Cadence products to optimize power, space, and energy needs for a wide variety of market applications. To learn more about our innovative solutions, talk to our team of experts or subscribe to our YouTube channel.