What are the characteristics of the LTE-M Antenna ?
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Does anybody have more information regarding the PCB antenna kit that is used for LTE-M and NB-IoT ? What is the expected radiation pattern ? Does it provide any gain ? Why do the recent versions have this copper clad shape attached, (the first ones did not)?
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@Cees_Meijer Yeah we measured SWR & cross checked it with RSRP reported by the modem. Many pcb style antennas fail to perform as well as a simple quarter wave ground plane or even a half wave dipole on band 28(750MHz). Not exactly sure why, could be compromises related to multiband (the PCBs are invariable multiband whereas the quarter/half waves are single band) or just that band28 is not included in the multiband design? In general many antennas advertised as LTE don't perform very well below 800MHz.
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@kjm From your answer I understand you actually did SWR measurements on the antenna ? And also that these specific ones are not very 'predictable their performance ?
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I'm guessing the addition of the copper plate was an attempt to improve performance by providing a bit of a ground plane? Both antennas have highly variable SWR on 750MHz (band 28) & probably the other lte bands too. Anyone's guess what the radiation pattern might be. Of the commercial multiband flexible pcb style antennas taoglas seem to have their act together with swr not fluctuating wildly when between a formica bench top & free air.