® Wang Electro-Opto Corporation ( ) Broadband Omnidirectional Helmet Antennas Johnson J. H. Wang Wang Electro-Opto Corporation Marietta, Georgia 30067

Wang Electro-Opto Corporation ( )WE O ®®

Broadband Omnidirectional Helmet Antennas

Johnson J. H. Wang

Wang Electro-Opto CorporationMarietta, Georgia 30067 USA

Presented in the 2006 IEEE AP-S International Antenna SymposiumAlbuquerque, NM

July 12, 2006

This research is partially supported by US Army CERDEC, Ft. Monmouth, NJ.


Outline

• Motivation

• Approach

• Brassboard Models and Field Tests

• Fieldable Retrofittable Model and Lab Tests

• Concluding Remarks


Motivation

• A helmet is generally worn in the field by soldier, police, firefighter, forest worker, and motorcycle rider, etc.

• The helmet-mounted antenna is the only antenna carried, borne, or worn by them that can possibly have a true and stable omnidirectional radiation pattern because of its– uniquely high and unobstructed field of view– stable orientation independent of the posture and

movement of the wearer (since the head is generally held upright).


Difficulties for helmet antennas

Helmet antennas in the literature are in early stages of development, with electrical and physical performance grossly below the expectations of user community due to the following difficulties.

– Antenna gain-bandwidth limited by helmet size – Safety issues on RF radiation and ballistic hazard – Stringent weight and size limitation– Competition for premium helmet location with

other equipment


The present approach

• Based on WEO’s patented SMM (spiral-mode microstrip) antenna and slow-wave antenna technology – ultra-wideband/multiband

– has inherent ground plane to shield the wearer from radiation hazard


RF design goals

• Frequency bandwidth: 1.35 – 2.7 GHz

• Polarization: vertical

• Radiation pattern: omnidirectional


Other design goals

• Safety requirements on RF radiation– ANSI/IEEE standard for “Uncontrolled Environment”

• Minimal ballistic effect to head of wearer• Maximum weight: 2 oz (56.7 gm)• Retrofittable to kevlar helmets• Producibility and low cost


Three models developed

• Two brassboard models (“Wang Ph 1” and “Wang Ph 2”) were developed first– both field tested by the US Army

• results summarized by the following two PPT slides prepared by Army CERDEC

• A fieldable retrofittable model recently developed– meeting all design goals in WEO lab tests– currently being field tested by Army CERDEC


Current Antennas Used for the Dismounted Soldier Pronounced Profiles - Easily Spotted By Enemy Susceptible to Body Blockage Effects - Poor Communications

in Certain Directions Susceptible to Damage from Foliage & Obstructions - No

Comms ! Are Narrowband and Tailored to a Single System - Can’t

Support New JTRS & SLICE Waveforms !

Good Comms InGood Comms InAll DirectionsAll Directions

Good Comms InGood Comms InAll DirectionsAll Directions

No Body Blockage !

WANG BODY WEARABLE HELMET ANTENNA

Quick Connect / Disconnect Connector

No Comms In No Comms In This DirectionThis Direction

No Comms In No Comms In This DirectionThis Direction

Body Blocks Comm in Forward

Direction !

TYPICAL DISMOUNTED WHIP ANTENNA

vs

Covers SLICE Soldier Radio Waveform (1350-2700 MHz)

Antenna Weight : 4 oz

Can Be Retro-Fitted To Existing Helmets In Field

Cost Effective - Reduced Attrition Rates

Material courtesy of U.S. Army CERDEC


C4ISR Demonstration Process Line-of-sight Range Measurements (Whips and Helmets) Evaluate Range Measurements Perform a Voice Communication Test With ARC Radio System Using the

802.11 Whip Antennas and Helmet Antenna Perform a Data Transmission Test Using the Commander Handheld

Application for Mission Planning (CHAMP) Software Using the 802.11 Whip Antennas and Helmet Antenna

Evaluate Performance of Helmet Antenna Based on Soldiers’ Comments

C4ISR Demonstration Process Line-of-sight Range Measurements (Whips and Helmets) Evaluate Range Measurements Perform a Voice Communication Test With ARC Radio System Using the

802.11 Whip Antennas and Helmet Antenna Perform a Data Transmission Test Using the Commander Handheld

Application for Mission Planning (CHAMP) Software Using the 802.11 Whip Antennas and Helmet Antenna

Evaluate Performance of Helmet Antenna Based on Soldiers’ Comments

Specialist E4 Ronald D. of 104th CAV wearing the Wang Phase II helmet

Better RF Range Performance than Larger, Narrowband Whip Antenna

Material courtesy of U.S. Army CERDEC

Notable Features - Helmet Antenna Completely Reduces the Visual Signature

- No Bending Required ! Not Subjected to Body Blockage Isolated From Metallic Obstructions in the

Soldier Wear Wide Band Operation

Notable Features - Helmet Antenna Completely Reduces the Visual Signature

- No Bending Required ! Not Subjected to Body Blockage Isolated From Metallic Obstructions in the

Soldier Wear Wide Band Operation


Annular zone on helmet clear of obstructions for optimal performance

No obstructions allowedin the annular zone


The latest fieldable retrofittable model

• Meeting ALL the design goals• 2 oz (56.7 gm) in weight• Currently being field tested by the US Army


Measured Standing Wave Ratio (SWR)

Model #A123J14

2

1


Measured radiation patterns over 1.35–2.7 GHz

Elevation

Model #A123J14

5 dB/div

1.350 GHz 1.800 GHz 2.700 GHz2.250 GHz

y

x

φ

θ = 90°

Azimuth

1.350 GHz 1.800 GHz 2.700 GHz2.250 GHz

z

x

θ

φ = 0°


Measured peak gain over 1.35 – 2.7 GHz

Model #A123J14

Peak Gain

-10.0

-5.0

0.0

5.0

10.0

1 1.5 2 2.5 3

Frequency, GHz

Pea

k G

ain

, dB

i

Discone on 24" gnd plane

Wang Helmet AntennaModel#A123J14

Pea

k G

ain

, dB

i


Fieldable retrofit helmet antenna weighs only 2 oz

• Antenna assembly made of lightweight foam, thin copper sheet, PC board, and flexible feed cable in a thermochemical composite

• Conductive foil lining shielding wearer’s head

• Quick-snap-on connector at helmet edge


Conclusion

• A fieldable retrofittable helmet antenna covering 1350-2700 MHz has been developed.

• It has major advantages over other antennas:

– invisible and safe

– stable and broad omnidirectional coverage

– weighs only 2 oz

– rugged (can withstand up to 70 lbs or more)

– field retrofittable

– producible at competitive cost

Documents

® Wang Electro-Opto Corporation ( ) Broadband Omnidirectional Helmet Antennas Johnson J. H. Wang Wang Electro-Opto Corporation Marietta, Georgia 30067