Sector Antennas 101 – Patch Arrays

Why are Patch Array (PA) antennas called arrays? How do they work? What are their advantages and disadvantages when used in WISP unlicensed networks? All these questions and many more are answered in our webinar dedicated to this technology!

Check out our PA sector optimized for suppressed noise and excellent performance in 5 GHz WISP networks: https://rfelements.com/products/array…

PA are one of the most used antenna types out there. They are cheap, easy to manufacture, and easy to adjust the design to increase or lower the gain depending on what is needed. However, in 5 GHz unlicensed networks, this antenna type is the cause of the biggest issue with noise. More precisely, the side lobes and frequency instability of PA sectors.

The side lobes (SLs), despite being weaker than the main lobe, transmit and receive the signal from unwanted directions. Since in unlicensed bands anyone can deploy as many devices as they please, it is just a matter of time when there so many that even the side lobes become a serious noise source leading to complete halt and collapse of the network.

This already happened in 5 GHz unlicensed band. The SLs can be mitigated but unfortunately not in a way that is suitable and attractive in WISP networks.

PAs have a few advantages that make them still dominate the sector coverage in WISP networks – they are affordable, and scalable for high gain. These are the only advantages of PA antennas for unlicensed bands.

On the contrary, the frequency instability, imbalance of performance between H and V polarizations, strong SLs, and radiation pattern shape make them unsuitable for WISP networks. Low Beam efficiency (https://youtu.be/U8x71RgK-_I) sums the SL problem up vey well. Instead, sector antennas in unlicensed bands should have Beam efficiency as high as possible.