Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

Questions tagged [radiation-pattern]

30 questions
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Phased Array Pattern

I'm working on a passively scanned phased array radar project, as a concept and hopefully design. One of the things that bugs me is that antenna patterning used. The vast majority of radar arrays I've seen employ a hex grid pattern, with a small…
Oliver
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How to derive antenna gain from radiation pattern

I need to calculate the antenna gain in both dimensions: azimuth and elevation. The datasheet of the antennas I am using has two different radiation patterns, one for the elevation and one for the azimuth. Given the two angles I can derive 2…
gabriel-shatana
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what is main reason for formation of side lobes in directional antennas?

I would like to know why are side lobes formed along with main beam in an antenna. I asked one of my colleague and he explained me that its due to radiation of frequencies near to the required center frequency. I'm not sure about this explanation…
Aparna B
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Dipole antenna radiation field equation

Can anybody provide me with an idealised formula that describes the radiation pattern of an omnidirectional dipole antenna? In particular I am interested in the formula that creates a plot similar to the following: Note: I am looking for a…
David
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What is the easiest way to eliminate a beam antenna's backward radiation (rear lobe)?

I tried a metallic reflector which works well in terms of radiation, but considerably degrades the return loss and adds more complexity to the design.
bibi
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Rhombic Polarization Question, provided radiation maps

I am trying to engineer my first antenna to get on the air. I need to hit a repeater 50 miles away at a lower elevation than me so that I can use its IRLP nodes. Would this mean I am looking for low angle radiation? 25 feet up with an HT in the…
Zeke Legge
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What's the general difference between radiation patterns of stationary and adaptive aerials in mobile communication systems?

I am trying to find general difference between radiation patterns of adaptive and stationary antennas (common difference, calculation difference and any other). I am interesting in any example and better any science publication on this theme.…
user3417815
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Do the Horizontal Conductors of a Ground Plane Antenna Adequately Decouple Its Feedline?

A NEC4.2 analysis of this configuration may reveal an unexpected truth about this...
Richard Fry
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Do Far-Field Radiation Patterns/Gains of NEC Software Accurately and Always Show the E-M Fields "Launched" by Vertical Monopoles?

Judging from posts on the Internet, this belief commonly is considered to be valid. But what is the correct answer?
Richard Fry
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What are the effects of a ground plane under a horizontal dipole?

What are the effects on signal propagation if this ground plane is just a metal object and what are the effects if the ground plane is actually grounded? I am asking this question because someone wants to put a storage container under my 40m antenna…
Synaps3
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Ham operators often tell me that comparing gain to an isotropic radiator isn't much use because it's only a theoretical antenna, is this true?

When you look down on an isotropic radiator from above, ie : the azimuth view radiation pattern, it's a circle. The same as looking down on any omni directional antenna. So when comparing the gain of a yagi antenna in the azimuth view at 0 degrees…
Andrew
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Antenna Patterns and Multipath Effect

It's said that in order to decrease multi-path effects on receiving antennas that your antenna pattern should have a sharp slope near the horizon. Why? for example this is article mentioned it.(Comparative Study of High-Performance GPS Receiving…
mahyar p
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How Might Nearby Re-Radiators Affect the Radiation Patterns of a Transmit Antenna?

Here is one example of such, based on a NEC study...
Richard Fry
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Antenna Q vs pattern shape

Is there any reason to think that changing the Q of an antenna would affect the directional pattern, assuming that is the only variable that changes? Restricting to values of Q say less than 1000. Assume this is an HF loop antenna which could reach…
user103218
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Would a covering like aluminised kapton effect antenna radiation pattern?

I'm looking at using a 1/4 wave whip antenna for a transmitter. If possible I'd like to cover the antenna in very thin (0.02 mm) aluminised kapton for reasons unrelated to the radio system; to be clear the Kapton will not be directly touching the…
FraserOfSmeg
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