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== Antennas

There are two styles of antennas in use in COSMOS. The first style is directional and used exclusively as part of the large node sectors. The second style is omni-directional and used as part of the medium nodes.

|| [[Image(directional_antenna_mudd_500px.jpg, height=400px)]] || [[Image(medium_antenna_120th_500px.jpg, height=400px)]] ||
||  Large node sector antenna (directional)  ||  Medium node antenna (omni-directional)  ||

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=== Directional (large node sector)
The directional antennas are comprised of a horizontal array of four [attachment:RFSpace_TSA900_directional.pdf ultra-wideband antenna elements]. Each element is oriented in the vertical plane and spaced 3 inches (7.63mm) from its neighbor. The frequency range covered by the antennas is 900 MHz - 12 GHz. However, due to limitations in the power amplifiers, USRPs, and other RF front end components, the actual frequency ranges are 2.4 - 6 GHz for transmit (non-contiguous, [wiki:hardware/rf-front-end see RF front end for details]) and 900 MHz - 6 GHz for receive.

A GPS antenna is located near the transmit/receive antenna and provides the GPS signal to the USRPs in the node.

|| [[Image(directional antenna inside.JPG, height=300px)]] || [[Image(s1+s2-lg1_roof.jpg, height=300px)]] ||
||  Directional antenna interior with element numbering  || s1-lg1 and s2-lg1's directional antennas from Mudd rooftop ||

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=== Omni-directional (medium node) without mmWave devices
The omni-directional antennas are comprised of four vertically oriented [attachment:MobileMark_RM-WHF_omni.pdf​ multi-band antennas] in a 6” (15.24 cm) 2x2 square pattern with a 14.25”x14.25” (36.2x36.2 cm) ground plane. The frequency range covered by the antennas is 1.7 - 6 GHz. However, due to limitations in the power amplifiers, USRPs, and other RF front end components, the actual frequency ranges are 2.4 - 6 GHz for transmit (non-contiguous, [wiki:rf-front-end see RF front end for details]) and 1.7 - 6GHz for receive.

A GPS antenna is located in the middle and provides the GPS signal to the USRPs in the node.

|| [[Image(medium antenna unpainted.JPG, height=300px)]] || [[Image(medium antenna top down view.png, height=300px)]] || [[Image(md1_street.jpg, height=300px)]]
||  Unpainted omni-directional antenna  ||  Antenna element numbering  ||  md1's omni-directional antenna from street level  ||

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=== Omni-directional (medium node) with dual mmWave devices
The mmWave version of the medium node antenna housing has the same configuration for the sub-6GHz and GPS antennas as the medium node configuration above. The main difference is in the addition of:
 * Dual [wiki:/wiki/Hardware/SubSystems/IBM IBM 28GHz Array]
 * Fans for cooling the mmWave arrays
 * Dual cameras

||  [[Image(medium_mmwave_antenna.jpg, height=300px)]]  ||  [[Image(medium_mmwave_antenna_deployed.jpg, height=300px)]]  ||
||  mmWave & omni-directional sub-6GHz antenna  ||  Deployed antenna at CCNY  ||

The mmWave arrays are installed at 45 degrees and down-tilted 12 degrees to give optimal street level coverage. The "window" for each mmWave array is a 5" x 5" opening covered with a 1/8" scratch/impact resistant polycarbonate to protect the array elements.

Design files for the mmWave medium antenna:
 * [attachment:Medium_Antenna_Dual_PAAM_Drawing_Main_Box.pdf Main box CAD drawing]
 * [attachment:Medium_Antenna_Dual_PAAM_Drawing_Bottom_Plate.pdf Bottom cover plate CAD drawing]