Contents
What is the effect of ground on antenna radiation pattern?
Waves radiated from the antenna directly downward reflect vertically from the ground and, in passing the antenna on their upward journey, induce a voltage in it. The magnitude and phase of the current resulting from this induced voltage depends on the height of the antenna above the reflecting surface.
Why is the antenna size reduced?
More reduction in size is achieved at the cost of narrower bandwidth. This is expected because the bandwidth of an antenna is related to the electrical volume of its radiation.
Do Antennas need to be grounded?
Do I Need to Ground my Outdoor Antenna? Yes, all outdoor TV antennas should be grounded. Even if you have a newer plastic antenna, there is metal inside. Furthermore, TV signals are made of electricity.
Why do we ground antenna?
Grounding will eliminate static electricity, as well as protect against energy to the mast if the antenna comes in contact with live electrical wires. Outdoor masts should be grounded with Grounding Conductors (see F in diagram) to the building’s Power Service Grounding Electrode System (see E) at a permitted location.
How do I reduce the size of my antenna?
Size Reduction Techniques
- Use of Shorting Wall — Quarter Wave Patch. Introduction. Formula for resonant frequency. Experimental results.
- Partially Shorted Patch and Planar Inverted F Antenna.
- Use of Shorting Pin.
- The Folded Patch.
How does ground plane size affect antenna impedance?
I am no RF expert, but I do know as you change the ground plane size you change the field distributions at the edge of the antenna. Thus, if you keep your feed point in the same spot the impedance will have changed due to the field distribution change.
How does the height of an antenna affect the feed point resistance?
In other words, the feed-point resistance of the antenna is affected by the height of the antenna above ground because of mutual coupling be- tween the antenna and the ground beneath it. The electrical characteristics of the ground affect both the amplitude and the phase of reflected signals.
How big should the ground plane be for a magnet Mount antenna?
So as long as I plop my magnetic mount antenna in the middle of a piece of conductive metal at least 1 foot in diameter, I’m good to go… (for GMRS). Simply calculate for your own frequency. If you’re doing it for a UHF mag-mount antenna for say, 150 MHz, you’re looking at a ground plane diameter of 3.1 feet.
Is it possible to increase the gain of an antenna?
If higher gain is desired, the antenna must necessarily be a narrow-band device. In fact, the input impedance becomes frequency sensitive so rapidly that, for large antennas, no significant increase in gain over that of the uniformly illuminated aperture is possible.