Helix Antenna vs. Patch Antenna: Key Differences Explained

This article breaks down the key differences between helix antennas and patch antennas, two common choices for applications like GPS. We’ll explore the basics of each antenna type and highlight their strengths and weaknesses, helping you understand which might be better suited for your needs.

Patch Antennas

Patch antennas are often found on rooftops and other surfaces due to their ability to achieve high gain when mounted above a large ground plane. Ceramic patch antennas are popular because they can be manufactured in smaller sizes, typically ranging from 10x10 mm² to 25x25 mm².

Figure 1 illustrates the radiation pattern of a patch antenna. Patch antennas with smaller ground planes can exhibit a back-lobe in their radiation pattern, making them susceptible to interference from the backside. The figure also demonstrates the optimal placement of the patch antenna for achieving the best performance.

Several design considerations are important when working with patch antennas:

• Avoid mounting any components near the patch.
• Maintain a sufficient minimum distance between the antenna and the device housing.
• Avoid routing signal lines near or under the antenna.

For more in-depth information, you can refer to articles specifically on microstrip patch antenna design.

Helix Antennas

Helix antennas can be designed with or without a ground plane. Figure 2 depicts the radiation pattern of a helix antenna without a ground plane.

As the figure shows, the radiation pattern is omni-directional. While helix antennas generally don’t require ground planes, adding one can significantly improve performance. If used, the ground plane should be kept at a minimum distance from the radiating portion of the helix antenna. Helix antennas can be used internally within a device or as external free-space antennas, often for satellite signal reception.

Key Differences

• A patch antenna can achieve comparable gain in a smaller size compared to a larger helix antenna.
• Helix antennas tend to have lower sensitivity than similarly sized patch antennas.

Advantages and Disadvantages: Helix Antenna vs. Patch Antenna

The following table summarizes the pros and cons of each antenna type: