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Antennas for Defence Applications

SPIRAL ANTENNAS

The first locally manufactured high performance 2 to 18 GHz spiral antennas for airborne applications were developed by me in the 1970s and 1980s. These spiral antenna designs were extended to spiral antennas operating in the 150 MHz to 40 GHz frequency range. Some of these designs were adapted to be high pressure spiral antennas for submarine applications. Customised spiral antenna designs were implemented for:

Amplitude comparison DF systems: 2-18, 2-40, 0.5-6, 0.5-18, 18-40 GHz arrays and ultra-compact 0.7-40 GHz spiral antenna with integrated diplexer to split band at 18 GHz. High pressure spirals for submarine applications (2-18, 2-6, 6-18 and 18 to 40 GHz).

Interferometer DF systems: Precision spiral antennas with phase and amplitude tracking performance in 0.5-2 GHz, 2-6 GHz, 6-18 GHz and 2-18 GHz sub-bands.

High-pressure phase track spirals: Submarine applications in the 2-18 GHz range.

LOG PERIODIC DIPOLE ARRAY ANTENNAS (LPDAs)

Developed a range of ultra-compact LPDAs operating from 20 MHz where the elements are the longest and these element lengths are reduced by means of inductive loading. This decreases mass and wind loading for tactical antennas. Frequency ranges span 20-3000 MHz in a single antenna for spectrum monitoring (also LPDAs for sub-bands in this range). High power (1500 WCW) ruggedised LPDAs covering 80-600 MHz for helicopter borne stand-off jamming applications. Various etched LPDAs covering 0.5-40 GHz for radar simulators and as feeds for spinning DF antenna reflectors (1-40 GHz single feed).


HORN ANTENNAS

Designed and developed a wide range of horn antennas covering 0.5-40 GHz range including 9:1 bandwidth double-ridged horns. High power horns for jamming applications in the 0.8-18 GHz range. High power slant 45 polarizers for jammer horns. Circularly polarized horns with dielectric lenses for beam shaping.


BLADE ANTENNAS

Blade antennas were developed for high performance and transport aircraft with particular emphasis on phase tracking performance for airborne interferometer DF systems covering 25-500 MHz and 500 MHz-2 GHz.

OMNI-DIRECTIONAL ANTENNAS

An extensive range of biconical omni-directional antennas with slant 45 polarizers operating in the 0.5-40 GHz frequency range was developed. All antennas are radome enclosed and suitable for airborne, shipboard and some special omnis for submarine applications. Some broadband models (1-18 GHz) employ beam broadening techniques to maintain acceptable beamwidths at the high end of the frequency range. Where an individual antenna cannot cover the desired frequency range, antennas are stacked with internal cable routing (for example, 1-18 GHz stacked with 18-40 GHz omni on top). Radome enclosed monopole and stub antennas operating in the 1.5-18 GHz frequency range were developed to augment the range of biconical antennas where compact structures are required for airborne applications.

ANTENNA ASSEMBLIES

The above antennas (and others) have been incorporated into higher value assemblies for systems applications where some of the key technological problems were solved by me.

  • Low profile spinning DF antennas (the rotodome concept) covering 0.7-18 GHz (option to 40 GHz) in sub-bands using LPDA arrays and pillbox type horns all are slant 45 polarized. Larger 0.5-18 GHz spinning DF assemblies with integrated omnis on top of radome. Suitable for helicopter and transport aircraft applications.
  • 1-40 GHz spinning DF system with shaped reflector and 1-40 GHz LPDA feed and integrated omni stack.
  • Integrated amplitude comparison DF systems (4 x 90 sectors 0.7-6, 6-18 GHz with integrated omnis)
  • DF interferometer panels with phase matched spiral antennas including radomes and cabling to receiver interface (panels cover 0.5-2, 2-6 (or 1-6) and 6-18 GHz).
  • Compact integrated interferometer DF assemblies for submarines using high-pressure spirals (2-6, 6-18 GHz) and high-pressure 2-18 GHz slant 45 omnis with integrated L1/L2 GPS
  • High power jamming arrays with spatial power combining to achieve high effective radiated power (ERP), also with high power slant 45 polarizers.
  • Communications Intelligence (COMINT) gathering antenna assembly for submarine applications with a radome qualified to 78 bar.