NOTE: It is observed in the literature that for narrowband antenna arrays, the distance commonly used for Phased-array technique is λ / 2.
i THINK the general distance between antenna element is either λ / 2 or as closest as λ / 4 for typical antenna. However, i never studied the requirement (for distance between element) for the case of Phase array technique. It might be different. Please, correct me if am wrong. Thank you
Dear Raimi Dewan, you have every reason, however my doubt is about the distance for UWB applications. In this case, as the bandwidth is larger than 500 MHz, theoretically, there are several λ being a center frequency for a λ lower limit for the frequency, fl fo. I have found as a good distance between UWB elements for applying the technique Timed-array value of λ = 0.86 to 6GHz frequency with the lower and upper 5 GHz and 7 GHz, based on simulations in CST, but would like very much open space for this kind of discussion. My email is: [email protected], if you want to talk about it. Thank you for orientations.
how about things like this:
| | | | | || | | | | |
the distance between each elements are not fixed. Closer to the center, shorter. For different wavelength, different elements could be as an array. I have seen antenna array like this about radio astronmy. But there's still a upper limit and lower limit about frequence. And if you have only a few elements, it's useless...... And I'm sorry that I know little about timed-array, so, maybe it's useless. But still wish it useful to you.
I'm sorry, I'll type the array again......
|.....|.....|...|..|.|.|..|...|....|.....|
forget those points, the " | " are antenna elements
Dear A. De Oliveira , certainly, for the case of UWB antenna, the bandwidth is in broad range (3-10.6 GHz) =)
i think i wanna have some brief reading on Timed-array application first. =) thank you
Dear Helen Wong, very interesting, his approach on the subject, I will investigate this idea! I know, no way to change the characteristics of beamforming varying the following characteristics: signal amplitude at each element, phase (for narrowband signal), time (for UWB signal) and as you mentioned as well, the distance between the elements. I'll keep investigating and will soon post my results. Thank you for your support.
Dear Dr. Dewan and Dr. Wong, if you wish we might start collaborative studies on the subject. My contact details are: [email protected], [email protected] or [email protected]. My skype is amanicoba. Thank you for the ideas.
I’m not expert for UWB arrays, but non uniform elements distribution is a good approach. I was dealing a lot with non-uniform distributed two-dimensional arrays and there are lot of benefits that you can get from it such as higher gain, lower side-lobes and wider bandwidth for the fixed number of elements. I think that it is quite applicable for UWB.
A. De Oliveira: you said "'ll keep investigating and will soon post my results"
do u already have them now? =)
Have preliminarily, simulation based datas, and as I said earlier, the best distance found was 0.86 λ at 6GHz. In will soon comment on the data of the experiments.
Dear fellow researchers.
A few days ago I presented at IEEE MTT-S IMOC 2013, part of the results of my research on this topic. I invite them to read the paper and discuss the subject further on the ideal distance to timed-array antennas, in contrast, arrangement of phased-array antennas.
The paper is titled: A Complete CMOS UWB Timed-Array Transmitter with a 3D Vivaldi Antenna Array for Electronic High-resolution Beam Spatial Scanning.
Dear Gholami,
Actually you are right, I will intensify my studies focused in variation of parameters to search for lower side emissions and better patterns of irradiation and control. I recently made a set of simulations and noticed that the distance of 6/7 λ 6GHz allowed better control of variation of the beam. The paper was presented at the IEEE IMOC 2013 with the title: A Complete CMOS UWB Timed-Array Transmitter with a 3D Vivaldi Antenna Array for Electronic High-resolution Beam Spatial Scanning, which is available on my profile. I invite you to analyze the results presented in the paper.
Thanks for the suggestions and support.
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