What are the antenna parameters required for 4G LTE advanced technology? Please explain in detail!
1. No. of Antennas (I believe it is 8*8 or 8*4). But why?
2. Radiation Pattern?
3. Beamwidth?
4. Gain?
5. Specific Absorption Rate?
6. Bandwidth (20 MHz*5 = 100 MHz channels through carrier aggregation).
7. Efficiency?
8. Polarization?
DearSuhas,
there are two antennas, the mobile user equipment or enode B antennas. I think you mean the base station antennas.
For specifications please see the link: http://mt-system.ru/sites/default/files/docs/by-lte-06.pdf
Best wishes
If you are looking for an antenna for LTE Advanced, then the operating frequency ranges are probably the most important, followed by the number of antennas.
1. No. of Antennas (I believe it is 8*8 or 8*4). But why?
The number of antennas helps to increase the capacity. The more antennas, the faster you can transmit/receive (as each antenna can send its own bitstream) and/or the more users you can serve. The actual number of antennas is determined by the limitations of the equipment (how many RF ports/channels the specific equipment can support). The latest base stations (BS) can have large (e.g. 8*8) MIMO arrays. The user equipment (UE) terminals are limited in size (to fit in the palm of a hand) and so cannot fit so many antennas.
2. Radiation Pattern?
3. Beamwidth?
4. Gain?
These are all related. The gain tells how well antenna focuses the electromagnetic radiation and thus how far it can send the signals. The gain is directly linked to the beamwidth. The narrower the beamwidth, the higher the gain. You can see a compromise here - it is possible to either send signal far (but in one direction) or cover a large area around the BS.
The radiation pattern describes the shape of the gain versus angle. Most antennas for BS are designed to radiate within a given sector (e.g. 120 degrees wide).
Well.. I must add that the No of antennas adds a multiplier effect here. Subject to applying appropriate signal processing techniques, one can consider that effective gain due to N antennas can be made to be N times higher than the gain due to a single antenna. Thus, a BS can choose to use many antennas to reach a far away user or to send intensive data stream to a nearby user or it can use each individual antenna to connect to a different group of users etc. The more antennas one has, the more flexibility one can afford, in addition to just capacity.
5. Specific Absorption Rate?
The SAR is mainly relevant to the UE antennas (as the SAR should be limited, to avoid directing too much energy into person's head or arm). The SAR is usually regulated by local regulators (spectrum or health ones).
6. Bandwidth (20 MHz*5 = 100 MHz channels through carrier aggregation).
The aggregation feature refers to aggregating the channels within the same frequency band (e.g. 2100MHz) or can be used to aggregate channels over different frequency bands (e.g. 1800MHz and 2100MHz).
7. Efficiency?
The efficiency for BS antennas is usually high (90% and up) whilst the efficiency for UE antennas is more difficult to make high.
8. Polarization?
Usually vertical polarization.
I do not know if something like this
http://www.ent.mrt.ac.lk/~ranga/courses/en4620_2010/L02.pdf
or
http://www.faculty.jacobs-university.de/jwallace/xwallace/courses/ap/ch3.pdf
may assist.
Dear Suhas,
Albert gave some explanations for the antenna parameters. As for the user equipment Antenna i would like to pay your attention to the paper in the link:Article Design of a Planar MIMO Antenna for LTE-Advanced
. It gives a possible design for the MIMO array in the user equipment.It is so that for single user MIMO, the space available to install the antenna is very limited. So, the number antennas will be limited to an upper limit as compared to the number of antennas in the Base stations.
Best wishes
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