Near Field millimeter Wave Antenna Measurements
(2023) EITM02 20231Department of Electrical and Information Technology
- Abstract
- In the real world, understanding an antenna's radiation pattern is crucial for its proper utilization. Typically, antennas are tested in the far-field region, where the radiation lobes are fully developed and phase errors are less than pi/8. However, due to some drawbacks like an increase in far-field distance for antenna arrays, researchers have shifted towards near-field measurements. These near-field measurements are then used to implement algorithms that predict the antenna's radiation pattern in the far field. In this thesis, an algorithm is developed in MATLAB to predict the far-field pattern of a horn antenna and estimate its gain at frequencies of 28 GHz and 39 GHz. Additionally, probe compensation is implemented to eliminate the... (More)
- In the real world, understanding an antenna's radiation pattern is crucial for its proper utilization. Typically, antennas are tested in the far-field region, where the radiation lobes are fully developed and phase errors are less than pi/8. However, due to some drawbacks like an increase in far-field distance for antenna arrays, researchers have shifted towards near-field measurements. These near-field measurements are then used to implement algorithms that predict the antenna's radiation pattern in the far field. In this thesis, an algorithm is developed in MATLAB to predict the far-field pattern of a horn antenna and estimate its gain at frequencies of 28 GHz and 39 GHz. Additionally, probe compensation is implemented to eliminate the influence of the probe's radiation pattern. In this study, planar near-field measurement techniques have been employed to scan the radiation pattern, which comes with angle constraints. Additionally, an effort has been made to extend this approach to active antennas by utilizing a Phased Array Antenna Module (PAAM) board. However, due to time limitations, only an estimation of the gain of the PAAM board has been conducted. In the discussion of the results, potential reasons have been identified to justify any deviations from the expected results. Finally, future work has been proposed to enhance the implemented algorithm and achieve more accurate results. (Less)
- Popular Abstract
- Understanding how antennas emit signals, even though they are invisible, is truly fascinating. But why is it important to know how antennas radiate signals? The answer is quite simple: if a user doesn't receive a signal properly, they won't have the best experience. Let's imagine someone is on a phone call; if they don't get a good signal, the conversation won't be clear. So, for everyday situations like this, knowing about antenna radiation patterns is crucial. However, measuring these radiation patterns needs to be done from a considerable distance away from the antenna. The reason for this is that when you're very close to the antenna, the signal isn't as strong as you might think. Unfortunately, it works the other way around. If the... (More)
- Understanding how antennas emit signals, even though they are invisible, is truly fascinating. But why is it important to know how antennas radiate signals? The answer is quite simple: if a user doesn't receive a signal properly, they won't have the best experience. Let's imagine someone is on a phone call; if they don't get a good signal, the conversation won't be clear. So, for everyday situations like this, knowing about antenna radiation patterns is crucial. However, measuring these radiation patterns needs to be done from a considerable distance away from the antenna. The reason for this is that when you're very close to the antenna, the signal isn't as strong as you might think. Unfortunately, it works the other way around. If the observer is very close to the antenna, the user might be in what's called the "near-field" region, where the antenna's signal pattern isn't fully formed. Also, in real-life situations, users won't always be sitting right next to the antenna when they use it.
Obtaining the far-field pattern through near-field measurements might sound confusing, but it's actually possible and quite useful. The reason for using this method is that in newer cellular generations like 5G or 6G, larger antenna arrays are used at higher frequencies, which means the far-field distance increases due to larger antenna array size, making direct measurements very challenging. So, measuring it in the near field and then using these measurements to estimate the far-field pattern is much more convenient. When you're transforming measurements from the near field to the far field, it's crucial to consider something called "probe compensation." But what exactly is a probe? Well, a probe is essentially another antenna used to measure the radiation of the antenna you're testing. Now, why do we need to compensate for the probe? That's because, just like the antenna being tested, the probe itself is also an antenna. It has its own radiation pattern, which can affect the measurements you take of the antenna under test. So, by doing probe compensation, we're essentially removing the impact of the probe's own radiation pattern from the data we've measured. This helps us get a more accurate picture of the antenna's performance.
By scanning in the near field, we can gain insights into antenna radiation. We can do these measurements on flat surfaces, curved surfaces like cylinders, or in spherical coordinates. Using this method has several advantages. It works well in small testing spaces, makes it easier to position antennas, helps detect near-field effects, and is cost-effective, among other benefits. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9140857
- author
- Manjunatha, Bharath LU
- supervisor
- organization
- course
- EITM02 20231
- year
- 2023
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Antenna Pattern, Near field to far field, Planar Scanning, Probe Compensation, Active Antenna
- report number
- LU/LTH-EIT 2023-957
- language
- English
- id
- 9140857
- date added to LUP
- 2023-11-15 11:47:24
- date last changed
- 2023-11-15 11:47:24
@misc{9140857,
abstract = {{In the real world, understanding an antenna's radiation pattern is crucial for its proper utilization. Typically, antennas are tested in the far-field region, where the radiation lobes are fully developed and phase errors are less than pi/8. However, due to some drawbacks like an increase in far-field distance for antenna arrays, researchers have shifted towards near-field measurements. These near-field measurements are then used to implement algorithms that predict the antenna's radiation pattern in the far field. In this thesis, an algorithm is developed in MATLAB to predict the far-field pattern of a horn antenna and estimate its gain at frequencies of 28 GHz and 39 GHz. Additionally, probe compensation is implemented to eliminate the influence of the probe's radiation pattern. In this study, planar near-field measurement techniques have been employed to scan the radiation pattern, which comes with angle constraints. Additionally, an effort has been made to extend this approach to active antennas by utilizing a Phased Array Antenna Module (PAAM) board. However, due to time limitations, only an estimation of the gain of the PAAM board has been conducted. In the discussion of the results, potential reasons have been identified to justify any deviations from the expected results. Finally, future work has been proposed to enhance the implemented algorithm and achieve more accurate results.}},
author = {{Manjunatha, Bharath}},
language = {{eng}},
note = {{Student Paper}},
title = {{Near Field millimeter Wave Antenna Measurements}},
year = {{2023}},
}