Questions tagged [radiation-pattern]
The radiation-pattern tag has no usage guidance.
29
questions
5
votes
2answers
95 views
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 ...
2
votes
1answer
66 views
Total radiation pattern in antenna arrays
let's consider a simple linear uniform spaced array:
We know that, from elementary array theory, the total pattern (for instance in terms of E-field) may be evaluated, in case no phase shift is ...
2
votes
1answer
102 views
Half wave dipole with parasitic element, (Gain calculation)
good morning all,
I have difficulties to find the correct formula that allows me to calculate the gain of half wave dipole in parallel with another parasitic half wave dipole.
I'm trying to calculate ...
2
votes
1answer
267 views
How Does the Performance of an Inverted V Dipole Compare to a Linear Dipole?
The NEC4.2 comparison in the answer below shows one example, for a practical set of installation conditions.
2
votes
1answer
133 views
How Much Does the Radiation Pattern of an "EFHW" Antenna System Vary Across its Bands?
This NEC4.2 analysis shows one example of such variation.
3
votes
1answer
143 views
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...
0
votes
1answer
56 views
What Are Some of the Most Important Characteristics Applying to the Radiation of Monopole Antenna Systems?
Such characteristics are described in Answer 1 below, as sourced in a study of antenna engineering textbooks, and by generating NEC4.2 studies.
3
votes
1answer
139 views
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?
1
vote
1answer
126 views
Need help understanding the gain on antenna pattern plots
My understanding is that the value of the axis (like -10 / 0 dB) refers to the maximum antenna gain (e.g. 12dbi).
So, if a ...
0
votes
1answer
74 views
Understand Radio Pattern of a WIFI antenna
I have a Fortigate AP, and need to understand its radio pattern for optimal positioning.
I've already understood the E-plane and H-plane representations and also that number on the circumference of ...
1
vote
2answers
179 views
How to plot transmitter coverage area?
As an Extra class licensee, I should probably know this... I am working on a web application for repeater owners. I would like to include an estimated coverage area, provided they have entered all of ...
3
votes
1answer
423 views
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 ...
3
votes
4answers
159 views
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 ...
8
votes
2answers
623 views
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 ...
5
votes
1answer
409 views
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 ...
2
votes
2answers
134 views
How Does the Low-Angle Radiation of a Horizontal Dipole Compare to That of a Vertical Monopole?
Conventional wisdom based on the far-field (only) patterns calculated by M-o-M software such as NEC show that low-angle radiation from a horizontal dipole is very low, and zero in the horizontal plane....
3
votes
1answer
96 views
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.(...
2
votes
1answer
67 views
How Might Nearby Re-Radiators Affect the Radiation Patterns of a Transmit Antenna?
Here is one example of such, based on a NEC study...
3
votes
2answers
509 views
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.
2
votes
2answers
88 views
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.
...
1
vote
3answers
234 views
How to calculate/estimate the effect of having conductive material nearby an antenna
I have a system with a 1/4 wave whip antenna and above the antenna there is a mess of aluminium they're not connected but are nearby. I would like to figure out what effect this would have on the ...
0
votes
1answer
116 views
Directional antenna overlapping main lobes
In a 2-Rx by 2-Tx directional antenna system, say both transmitters are transmitting concurrently as in Fig. The main lobes from the two transmitters overlap. How does this affect the resultant signal ...
8
votes
1answer
702 views
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'...
2
votes
1answer
212 views
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 ...
2
votes
1answer
796 views
Horizontal dipole radiation gaps
Consider the radiation pattern of a horizontal dipole mounted at a height of 1.75λ. Is it possible for a receiving station's antenna to be mounted at a certain height such that the radiation of the ...
2
votes
3answers
299 views
Can you place reflective material near to an antenna without interfering with the radiation pattern?
So I'm trying to understand how radiation pattern are calculated and it's going well (so far!). I've come across a bit of an issue when it comes to the following situation:
If we have a ...
3
votes
1answer
240 views
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 ...
3
votes
1answer
82 views
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 ...
2
votes
1answer
1k views
Radiation pattern for a 1/4th wave 2 meter antenna used on 70cm
What would the radiation pattern look like if I used a 1/4th wave 2 meter mag-mount antenna on 70cm with an HT.
