Fractal Antennas and cell phones

If you recall from about 15 years ago, cell phones and car phones all had large antennas that you typically pulled out before making a phone call. Here is one such phone picture.

Nowadays, cellphones and car phones dont seems to have such long antennas So where did these antennas go? Did we get technology that makes a phone work without an antenna? Thats not possible just yet.

What happened was that the fractal antennas were invented. The key feature of an antenna is its shape and the strength and quality of the signal received is a function of the length of the antenna. So the larger the antenna, the better the reception. How fractal antennas solve the problem is that they are made up of a shape that repeats it self (a fractal). Hence for a given length, a fractal antenna because of its folded self similar design occupies a very small amount of area. In fact, the shape of these antennas are commonly called “space filling curves”. Hence we are able to get a very long antenna in the smallest amount of space possible. This is the reason we dont need long external antennas. The antenna is built into the body of the phone.

Fractal antennas also have one other significant advantage. In various countries, cell phones operate in different bands of the radio spectrum. Cell phone manufacturers were faced with the need to build multiple antennas in order to make their phones work in these countries. However by taking a shape that can receive multiple bands and then replicating that into a fractal antenna, they are now able to make compact multi-band phone without significant increase in space.