Millimetrica has designed several antennas for special applications such portable logs, magnetic loops, collinear and parabolic prime focus reflectors. Most of this are custom design but usable for general purposes.
See also AM-DRM drive test antenna
| PORTABLE LOGs
Portable LOGs are logaritmic antennas for field measurement or "tactical purposes", where time and installation space are very limited, such to avoid using traditional antennas.
The main feature of the portable LOGs is the possibility to bend its elements on the boom, thanks to special metal joints like an umbrella structure.This allows the operator to "open" or "close" the antenna in a few seconds and to store it in a special tubular case.
Obviously the number of elements allowed by design is reduced and not comparable with traditional LOGs. For this reason the S.W.R. often is higher in some frequency segments, however because its excellent characteristics of portability and maneuverability, make it unique for field use.
Each antenna is delivered with a typ. Antenna Factor table, an SWR plot and a dielectric mast support.
We have two main design on VHF-UHF band customizable on other frequency ranges.
MIL ANT 174-900
|Frequency Range:||174-900 MHz|
|Number of elements:||15|
|Typ. gain:||4-5 dB|
|Download detailed data sheet|
MIL ANT 400-1000 (same structure as MIL 174-900)
|Frequency Range:||400-1000 MHz|
|Number of elements:||8|
|Typ. gain:||5 dB|
|Max. aperture (1° element opened)||38 cm|
|F/B ratio||20 dB|
|Connector:||N precision female|
|Materials:||Aluminium (boom and elements) ; steel (joints)
Polyprop. (mast dielectric support)
|Antenna weight||1 Kg|
|Mast suppor weight||0.5 Kg|
MAGNETIC LOOPs for MF and HFLoops antennas are commonly defined magnetic when the circumference is ≤ 1/8 or 1/10 lambda. One the main features of this antenna is to avoid any reflection plane and to achieve good directivity in a relative small radiating surface.Because this reasons they are largely used in anechoic chamber for EMC test and EMI measurement.See some of the available design below.
BROAD BAND ACTIVE MONO LOOPs (for receivers only)
We are mostly known for our crossed loop active antennas (AM/DRM), however we can design active mono loops for narrow or broaband applications in MF or HF bands. Please contact us for more information.
MIL MDFL 0517
Millimetrica can design collinears and GP antennas for wide frequency coverage or special applications
PARABOLIC DEFOCUSED ANTENNAs
|There are a huge number of parabolic antennas available in the market for many applications, however sometime it's not easy to find broadband coverage and/or wide radiation pattern. As much as the gain increases, as much the directivity rises, resulting in a main lobe very small. This is the reason why the antenna tracking could be extremely difficult and requiring high resolution step motors.
Usually parabolic reflectors and feeders are optmized for the best gain/radiation pattern Vs. narrow band range, requiring long distance far field zone. This could be a serious problem if the antenna is installed in an anecoic chambers.
EMC MIL radiated immunity test require to achieve high voltage field over very large frequency bands and typically the D.U.T. distance cannnot be very far from the antenna, due to the small space available in the room.
Other applications, such radar researches for educational purposes or small radar prototyping require to get small antennas featuring a at least few degrees aperture on the main lobe. This is in order to avoid buying necessarily a very complex and syntetic aperture antenna with related high costs.
Some of this applications can be covered by using defocused dishes, in which the feeder matches a compromize between the highest gain and a reasonable lobe aperture.
We can design antennas for this specific purposes and tasks. Please provide contact Millimetrica with your specifications.