Working Principles of FPC and PCB Embedded Patch Antennas

Embedded antennas in PCBs are a common solution in wireless devices. They are easy to design and manufacture, and they can be placed anywhere on the PCB. However, PCB embedded antennas are also very sensitive to the environment, which can affect their performance. This article will explore the working principles of FPC and PCB embedded patch antennas, their pros and cons, and what to consider when designing a wireless device with an embedded antenna.

What is a patch antenna?Working principle of a patch antennaAdvantages and disadvantages of patch antennasFactors to consider when designing a patch antennaConclusion

What is a patch antenna?

A patch antenna is a type of antenna that consists of a flat, rectangular metal patch mounted on a substrate. The substrate is usually made of a dielectric material, such as FR4 or Rogers, which helps to isolate the patch from the ground plane. The patch is typically fed by a microstrip line or a coaxial cable, and it can be either a dipole or a monopole.

Patch antennas are very popular because they are easy to manufacture and can be made very small. They are often used in wireless devices, such as cell phones, tablets, and laptops. Patch antennas are also used in satellite communications and GPS systems.

Working principle of a patch antenna

When a patch antenna is fed with an RF signal, the current on the patch causes the patch to radiate electromagnetic waves. The shape and size of the patch determine the frequency at which the antenna will resonate. The patch also determines the polarization of the radiated waves, which can be either linear or circular.

The substrate material and thickness also affect the antenna’s performance. A thicker substrate will result in a lower resonant frequency, while a thinner substrate will result in a higher frequency. The dielectric constant of the substrate material will also affect the resonant frequency and the bandwidth of the antenna.

Patch antennas are typically designed to operate at a specific frequency, which is determined by the size and shape of the patch. The frequency can be adjusted by changing the length of the microstrip feed line or by adding a tuning stub to the feed line.

Advantages and disadvantages of patch antennas

Advantages

Patch antennas are very popular because they are easy to manufacture and can be made very small. They are also very versatile and can be used for a variety of applications. Patch antennas are also relatively inexpensive compared to other types of antennas.

Disadvantages

One of the main disadvantages of patch antennas is that they are very sensitive to the environment. The performance of the antenna can be affected by the surrounding objects, such as walls, furniture, and even people. Patch antennas are also very sensitive to the dielectric material used for the substrate. If the dielectric constant of the substrate is not matched to the resonant frequency of the antenna, the performance will be degraded.

Factors to consider when designing a patch antenna

There are a number of factors to consider when designing a patch antenna, including the frequency of operation, the bandwidth, the gain, the efficiency, and the radiation pattern.

Frequency of operation

The frequency of operation is the most important factor to consider when designing a patch antenna. The size and shape of the patch will determine the frequency at which the antenna will resonate. The frequency can be adjusted by changing the length of the microstrip feed line or by adding a tuning stub to the feed line.

Bandwidth

The bandwidth of a patch antenna is the range of frequencies over which the antenna will operate effectively. The bandwidth is typically very narrow, on the order of 1% to 2%. However, it can be increased by using a thicker substrate or by adding parasitic elements to the antenna.

Gain

The gain of a patch antenna is a measure of how well the antenna will radiate or receive electromagnetic waves. The gain is typically very high, on the order of 10 dBi to 20 dBi. However, it can be increased by using a larger patch or by adding a reflector to the antenna.

Efficiency

The efficiency of a patch antenna is a measure of how much of the input power is converted to radiated power. The efficiency is typically very high, on the order of 90% to 95%. However, it can be decreased by using a lossy substrate or by adding resistive loading to the antenna.

Radiation pattern

The radiation pattern of a patch antenna is a measure of how the antenna will radiate or receive electromagnetic waves in different directions. The radiation pattern is typically very directive, meaning that the antenna will radiate or receive best in a specific direction. However, it can be made more omnidirectional by using a larger patch or by adding a reflector to the antenna.

Conclusion

Patch antennas are a popular choice for wireless devices because they are easy to manufacture and can be made very small. However, they are also very sensitive to the environment, which can affect their performance. When designing a wireless device with an embedded antenna, it is important to consider the frequency of operation, the bandwidth, the gain, the efficiency, and the radiation pattern. It is also important to choose a substrate material that is matched to the resonant frequency of the antenna. By taking these factors into account, it is possible to design a wireless device with an embedded antenna that will perform well in a variety of environments.