Well, we've finally started to truly put the “wired era” behind us, and good riddance! Wires just get in the way, cause tangles, trip people, and are basically more trouble than their worth. Modern wireless technologies make it far easier to install and maintain a network within your business than ever before, and they're allowing people to make bigger, faster, more widespread networks with little trouble.
So, let's take a quick look at some of the common kinds of WiFi antennas that are out there and how they're best put to use!
Omni-Directional: These are generally the most popular forms of antenna. They give you an even 360-degree broadcast radius, and are generally suitable for giving coverage to an entire room or, potentially, an entire floor. On the other hand, since they are two-way antennas, this also means they'll be picking up any interference around them as well. They also simply broadcast everywhere within their range, so it's easy for them to broadcast beyond your walls to people outside. (This may be a good or bad thing, depending on your circumstances.)
Directional Antennas: As the name suggests, these are more like the old “rabbit ear” antennas that have to be pointed in a particular direction to function. Since they have a limited directional range, these can be used to avoid major sources of interference. They're also good for setting up point-to-point networks where you're more concerned with connecting two nodes than with creating widespread access. In some cases, they can also be used to isolate your signal from the outside. (Such as a circular array of inwards-pointing antennas, to prevent outside leakage.)
Grid Antennas: These are more specialized, designed specifically for outdoor use and
Yagi Antennas: This is a particular form of directional WiFi antenna that is specifically designed for making point-to-point networks easier to set up and maintain. Imagine, for example, a hospital spanning two sides of a highway that wants to broadcast its WiFi to both sides at once. This is the sort of job a Yagi antenna performs.
Panel Antennas: You generally only see these on major communications outfits. They use flat fiberglass panels, much like those used in cell phone towers, which are both more aesthetically pleasing and often more powerful. They're also much more expensive. You probably won't need to look at these unless you're looking at having to broadcast at mile-sized distances.
So, like back in the HiFi days, your choice of equipment can still make a big difference on how your electronics perform. When you're looking to invest in new networking hardware, make sure to contact a qualified professional to ensure you're getting the best equipment for the job you need it to do!