antenna gain

Hello cookiesharma

Are these Class or Homework questions?

Kind Regards....

In a nutshell... (but vague),

The only way to increase the gain of any given antenna system is to make it more directional. Improving signal to noise ratio is the goal.

Q1. To increase the gain of antenna, it's depend on the antenna type. For example, if You use Yagi-Uda Antenna, you can increase its gain by tuning the antenna to get the SWR (Standing Wave Ratio) value as close as 1.0. You can use an SWR Meter to tune the antenna. Slide the "Gamma Match" until you get the best SWR value for your antenna (Close to 1.0). The second step is make sure the cable's impedance is 50 Ohm, or close to 50 Ohm. And if you have the tool (Antenna Analyzer), make sure the Capacitive Reactance (Xs) is 0, or close to zero in the frequency You want.

For your case (Gigahertz Frequency), if I'm not wrong, you can use helical antenna type.

Q2. Like I said before, the factors are SWR Value, Impedance, Capacitive Reactance, and of course the antenna type.

Hello again, cookiesharma

Q1) Use a parabolic reflector type of antenna at the GHz frequencies.

If you need mobile usage, incorporate a rotating antenna of that type, and include an "auto-seeking for strongest signal" system, which rotates the mobile antenna to point towards the fixed antenna at all times.

Q2) Power output is the largest factor.

Perhaps you might care to put some reply here, with

Kind Regards....

Another possibility for mobile use is a collinear antenna. At cell frequencies, this consists of sections of straight 1/2 wavelength antenna and a coil (to not radiate 1/2 wavelength), and ending at the top end with a half wavelength section. You can see this scheme in many cell phone antennas on cars For more gain, you just add more sections ad infinitum. There are variations on this type of antenna, but this is the basics.

I searched for "wiki collinear antennas" and got a whole bunch of info.

An antenna basically does not care whether it is transmitting or receiving. If your antenna has a gain which gives you 4 times effective radiated power, it will also give you 4 times the received power.

For a stationary location, I agree with Sparks. You can get lots of gain out of a dish.

Bill