1. The role of active millimetre wave radar in defence surveillance
Dr Duncan A. Wynn
SMI Conference
Radars in Defence
8th - 9th May 2006
The Hatton
London
Good afternoon ladies and gentlemen. My name is Duncan Wynn. I am the Principal Scientist at Q-par Angus Ltd, a UK based company that specialises in RF and millimetre wave technology. The company has UK MoD List X status and is based in Leominster, on the Welsh-England border with around 40 graduate employees. I am going to briefly talk about the role of active millimetre wave radar in defence surveillance. I will leave some time at the end of my talk for any questions that might arise.
Tel: +44(0)

2. Contents Why consider millimetre wave radar ?
– what roles do they play ?
Review of millimetre wave technology – filling the “THz gap”
Capability – performance, benefits and defence applications
Future
– higher resolution and improved detection at lower cost ?
I am going to consider why millimetre wave radar is important and what roles it plays in defence surveillance. I will briefly review relevant technologies and explain the significance of the so-called THz gap. The capability of millimetre wave radar will be considered including performance, benefits and various applications in defence. Finally, I will gaze into the crystal ball to see how this might evolve in the not-so distant future.

3. Why consider millimetre wave radar ?
Firstly, lets ask the question “why consider millimetre wave radar ?”

4. Electromagnetic spectrum
Millimetre
waves
Millimetre waves occupy a region in the electromagnetic spectrum between microwave and visible radiation. The designation of this varies in accordance with agreements between international organisations. I will be considering millimetre waves as electromagnetic radiation with a frequency between 30 and 300 GHz designated as EHF according to ITU. This corresponds to free- space wavelengths between 1mm and 10 mm. This covers Q, O and V-band according to the UK designation and Ka, Q, V and W-band according to US designations. I will extend the discussion, where relevant to cover submillimetre waves with free-space wavelength down to 0.3 mm at terahertz frequencies.

5. Why consider millimetre wave radar ?
Compact, small physical size and equipment weight
- Size, Weight And Power (SWAP) requirements are more likely to be met
for high mobility and covert users
Narrow antenna beamwidth with physically small aperture
Relatively low antenna sidelobes
Low spectral occupancy
- RF electromagnetic spectrum is sparsely occupied (at the moment !) at millimetric/sub-millimetric wavelengths
Availability of relatively large RF bandwidth (UWB)
slotted waveguide antenna
courtesy
Q-par Angus Ltd
So why consider millimetre wave radar ? The short wavelength of this electromagnetic energy has a direct impact upon the physical size of components and consequently leads to compact and relatively low weight equipment. The Size, Weight and Power requirements are more likely to be met using millimetre wave radar for high mobility and covert users. This is illustrated by the slotted waveguide antenna which has a 3 dB beamwidth of less than 1 degree at 95 GHz with a physical length of only 100 mm.
A relatively narrow antenna beamwidth results from the large number of wavelengths that can be fitted inside a physically small aperture. Relatively low antenna sidelobes can be designed but an advantage is that system responses through these can be attenuated by the atmosphere.
The spectrum is relatively sparsely occupied (at the moment !) and has a low spectral occupancy in the millimetre wave region. This makes it attractive for users that wish to exploit wide bandwidth with minimal problems concerning interference, both non-deliberate and otherwise, and covertness.

6. Frequency Attenuation by atmospheric gases, rain and fog
Masking or ‘self-screening’ effect of atmospheric attenuation
Reduced RF power density at remote sites
- low probability of exploitation (LPE) / minimal EMI/EMC problems
Covert operation
low propagation “overshoot”/ low probability of intercept (LPI)
excessive rain
150mm/hr
heavy rain
25mm/hr
drizzle
0.25mm/hr
A major disadvantage is the problem of attenuation by atmospheric gases and limits the maximum range at ground level.However, above the rain or freezing layer, at altitudes of 30,000 ft and above, the atmosphere is essentially unattenuating over a very wide frequency range. Consequently, radar performance can vary greatly with local temperature and humidity.
This phenomenon can be turned into an advantage since it affords “masking” or self-screening. The reduced RF power density at remote sites leads to low probability of exploitation (LPE) with minimal electromagnetic interference (EMI) and compatibility problems. There are distinct advantages for covert operation with the low propagation “overshoot”.
At frequencies below 1 THz, materials such as clothing and thin camouflage can be highly transmissive. Microwave anti-reflection materials usually contain absorbing matrices embedded within a plastic. These materials commonly have relatively low absorption in the THz region so that scattering from a target structure beneath them may be remotely sensed. This is the basis of so-called “see-thru-wall” systems.
10 GHz
100 GHz
1 THz
10 THz
100 THz
1000 THz
Frequency

7. What roles do they play ? Defence radar Surveillance and acquisition
Fire control and tracking
Instrumentation and measurements
Guidance and seekers
Numerous alternative roles (defence and non-defence related) including :
Medical and dental imaging, gene sequencing, ultra-fast chemistry for studying intermolecular interactions, charge movement and circuit diagnostics, security screening, hazardous chemical detection, Space Shuttle tile inspection, nanometre scale microscopy, Foreign Object Detection (FOD), automobile collision warning, UAV sense and avoid, environmental mapping etc ..
It will be appreciated that there are lots of roles, both defence and non-defence related. In addition to surveillance and acquisition these roles include fire control and tracking, instrumentation and measurements, guidance and seekers. I will concentrate only upon surveillance in defence systems for this talk although it is difficult to avoid overlap with Foreign Object Detection (FOD), collision warning systems and UAV sense and avoid applications.

8. Review of millimetre wave technology - filling the “THz gap”
Gunn InP
The generation of RF power is difficult in the range from 100 GHz to 1 THz. The “THz gap” refers to the challenge of providing convenient sources in this region, as illustrated by this diagram that plots maximum CW output power for available technologies.
These various technologies will be briefly explained later in this presentation.
Frequency (THz)

9. Generic millimetre wave radar
Modulator
Transmitter
Duplexer
Antenna
Synchroniser
timing/clock
Receiver
Receiver
protection
Signal
processor
Graphical
User Interface
The sub-systems of a typical mmw radar are basically the same as for a microwave radar. However, there are subtle differences. I am going to concentrate upon these in the transmitter, receiver and antenna sub-systems.
Antenna
control
Track processor

10. Transmitter
RF power sources needed in transmitter and receiver local oscillator
RF power (CW or pulsed), low noise (spurii, phase noise close to carrier), lifetime
Size, Weight and Power (SWAP) requirements (including cryo-cooling, if needed)
RF power from fundamental sources generally diminishes above 100 GHz
Frequency multiplication using non-linear devices to generate harmonics
provides much greater RF power above 100 GHz
typ. GaAs Schottky-barrier varactor or HBV diodes driven at 60 – 100 GHz
Diode arrays and MM MMICs as drivers typ GHz / GHz
It may be obvious but RF power sources are needed for use in the transmitter and receiver sub-systems.
The technical requirements are predominantly for RF power, either CW or pulsed. Low noise with minimal spurii and low phase noise noise close to carrier are also key. It should also be remembered that lifetime, robustness and reliability are issues for military equipment in particular.
There are usually Size, Weight And Power requirements. Usually, although not exclusively, the satisfaction of these favours solid state solutions. .
In general, the maximum available RF power from fundamental sources diminishes at frequencies above 100 GHz. Frequency multiplication is commonly used to overcome this. Often GaAs Schottky-barrier diodes varactor or heterojunction-barrier varactor diodes driven at GHz can provide a physically rugged RF source. Further examples are diode arrays driven by millimetre wave MMICs. A waveguide-based example is shown which typically can produce in excess of GHz.

11. Millimetre wave RF power sources
Solid state source technologies
- cavity stabilised Si/GaAs/InP Gunn diode
low cost
most powerful fundamental oscillators
within single semiconductor device
Impact Avalanche Transit Time (IMPATT)
Tunnel (Injection) Transit Time (TUNNETT)
Superlattice Electron(ic) Device (SLED)
Resonant Tunnel Diode (RTD)
- highest operating frequency 712 GHz
Quantum Cascade Laser (QCL) 2.8 THz
typical RF powers (peak)
310 mw @ 80 GHz
60 mw @ 94 GHz
GHz
3.7 mw @ 297 GHz
3.5 mw @ 300 GHz
> 1mw @ 325 GHz
> 0.6 mw @ 328 GHz
A lot of effort has been expended upon the development of solid state RF sources. Gunn diode based technology is claimed to offer the most powerful fundamental oscillators within a single device. Typical RF powers that are available between 80 and 328 GHz is illustrated. Record blazing results of GHz have been obtained using low noise InP Gunn devices.
I do not intend to detail each in the short time available. However, further technologies that are listed have been in development for many years.
The highest operating frequency of a solid state source has been achieved by Indium Arsenide Aluminium Antimony RTDs at 712 GHz but these produce only a microwatt of RF power.
The Quantum Cascade Laser is a most promising technology. This is a semiconductor laser based on intersubband transitions in quantum wells. If the operating frequency can be reduced to the low THz region then the narrow spectral line width and low noise make it ideal for receiver local oscillators. The wavelength is not controlled by the material band gap but by the layer thickness. Consequently, operation over a wide range of frequencies including THz, is possible. Modified semiconductor and lower loss waveguide structures are being developed to lower the operating frequency to within the 1 to 2 THz region, raise the output power and operating temperature.
courtesy
e2V Technologies Ltd

12. Millimetre wave RF power sources
Travelling Wave Tube (TWT) / Magnetron typ. 95 GHz
Free-electron laser (FEL) / Smith-Purcell
Extended Interaction Klystron (EIK) typ GHz
Extended Interaction Oscillator (EIO) typ. > GHz
Gyrotron / Gyro-klystron typ. 500 kW 95 GHz
typ GHz
Backward Wave Oscillator (BWO)
180 GHz to 1.5 THz
needs high voltage, magnetic fields and vacuum
Orotron (Ledatron) typ.>20w > 370 GHz
Super-radiance phenomenon ultra-high power pulses
typ. 300 Mw peak 200w mean at 38 GHz
Superconducting flux–flow oscillator
- needs cryogenic cooling
Molecular vapour laser - limited tunability
Synchrotron / Clinotron
Carcinotron typ. > 500 GHz
A wide range of millimetre wave RF power sources is available as illustrated with available powers from hundreds of watts (mean) to many megawatts peak. Again the prime power and cooling requirements should be considered alongside cost.
The Travelling Wave Tube can operate in both pulse and CW versions with a good mean power and a large bandwidth but it is rather costly unlike the magnetron.
More powerful sources using relativistic electron beams have been demonstrated, such as the free-electron laser and the gyrotron. These need high energy electron beams and high field magnets that are currently too bulky for mobile equipment.
The Extended Interaction Klystron (EIK) can operate in pulsed or CW mode and has a good mean power capability. Both amplifier and oscillator versions are available and the latter is relatively cheap.
Likewise, the Extended Interaction Oscillator (EIO) is a relatively low cost, CW source. In all cases, care needs to be taken to ensure that unintentional modulation imposed by inverter-based power supplies is outside the Doppler spectrum of interest.
Many interesting ideas have been proposed for using harmonic devices to reduce their size and power requirements, so powerful RF sources that are sufficiently compact for man-portable, mobile, aircraft and UAV systems may become a reality.
Examples of BWO devices

13. Receiver
Heterodyne techniques, as opposed to direct or video detection
generally superior sensitivity
relatively high spectral resolution
greater availability of devices
• “State of the art” … sensitive room temperature receivers are based upon
heterodyne mixers using GaAs Schottky barrier diodes
- up to 2.5 THz (>0.5 mw of LO RF power for low noise
performance and  5 mw for balanced receiver to cancel LO noise)
- demanding requirement for fundamental or harmonic semiconductors
Sensitivity improvements with low temperature devices
such as Superconductor-Insulator-Superconductor (SIS) tunnel junction mixer
and Hot Electron Bolometers (HEB)
Receivers have tended to use heterodyne techniques as opposed to direct or video detection methods. This generally results in superior detection and there is a wide availability of candidate devices since this technique is common in the fields of remote sensing and astronomy.
The most sensitive room temperature receivers are based upon heterodyne mixers using GaAs Schottky barrier diodes which can operate up to 2.5 THz. At least 0.5mw of local oscillator power is needed for low noise performance around 5 mw is needed for a balanced receiver to cancel local oscillator noise. This is a demanding requirement either for fundamental or harmonic semiconductor sources.
Further sensitivity improvements can be achieved with low temperature devices such as the SIS tunnel junction mixer that can approach quantum- limited performance with very low local oscillator power up to 1.2 THz and can achieve GHZ bandwidths. High sensitivities are also achievable with Hot Electron Bolometers and bandwidths of 5 GHz have been reported. Although superconducting receivers require coolers such as the multi-stage Stirling- cycle cooler, these can be quite compact in practice.
2.5 THz Nb HEB

14. Receiver IF amplifier integration
- integrated hybrid and MM MMIC technology has improved noise figure by minimising waveguide transitions
and couplings
Hermetic sealing
- cheaply by E-plane probe transition
Mixer diode overload protection
- back to back diode/PIN diode arrangement with overload protection > 1 watt (mean)
Extensive use of waveguide components
- extensive heritage to beyond 1 THz
- manufacture by precision machining
photolithography, electro-forming
and micro-machining
The integration of IF amplifiers with the use of hybrid and MMIC technology has improved the receiver noise figure by minimising, shortening the length or even removing waveguide transitions and couplings.
Fabrication techniques for hermetic sealing such as the E-plane probe transition and mixer diode overload protection are widely available.
Waveguide based components are extensively used up to, and beyond 1 THz and are manufactured by precision techniques that include micro-machining, photolithography and electro-forming.
manufactured by
Q-par Angus Ltd

15. Antenna
Most millimetric antenna designs are scaled variants of microwave approaches
Extensive use of reflector based antenna - dual-reflector (Cassegrain) arrangement
avoids waveguide losses associated with front-feeding
Lens and horn antennas avoid aperture blockage and sidelobe effects
Size and weight of lens based antennas are much less than microwave counterpart
Surface accuracy and stability more stringent than at microwaves
W-band Foster scanner
courtesy
Q-par Angus Ltd
Most millimetre wave antenna designs are scaled variants of microwave versions. The 94 GHz Foster scanner antenna shown is a hand-held variant of a vehicle-size 3 GHz microwave version.
There is extensive use of reflector based antenna design, particularly in which the dual-reflector or Cassegrain arrangement avoids waveguide losses associated with front fed configurations.
Lens and horn antennas can avoid the losses and poor sidelobe effects associated with aperture blockage.
Usefully, the size and weight of lens based antennas are much less than their microwave counterpart. However, the requirements for surface accuracy and component stability with temperature, humidity and vibration are much more stringent than at microwaves.
Q-band dielectric
immersion lens

16. Antenna Reflector antennas prime focus dual reflector (Cassegrain)
offset fed
shaped / reconformable reflector
• Lens antennas
dielectric immersion lens
zoned dielectric
Luneburg
• Horn antennas
flared
multimode
corrugated
lens corrected
• Dielectric rod
• Slotted waveguide antennas
• Leaky waveguide antennas
• Microstrip antennas
prime focus reflector
offset fed reflector
A wide range of antenna types is available.
slotted waveguide array
courtesy
Q-par Angus Ltd

17. on wood-pile structures
Antenna
Exploitation of novel materials
Electronic Band Gap (EBG) materials are structured dielectrics
which are photonic analogues of semiconductors
artificially engineered periodic materials to deter the propagation of
electromagnetic radiation over a specified band
- surface waves and back radiation are strongly suppressed within the bandgap
fabrication up to 500 GHz
Key features
periodicity
lattice geometry
dielectric constant
fractional volume
• Metamaterials / negative refractive index materials
• Millimetre wave active phased array based antenna
EBG waveguide
Novel materials such as electronic or photonic band gap and metamaterials with negative refractive index properties are being examined by many academic, industrial and government organisations.
Electronic band Gap materials are known as structured dielectrics which are photonic analogues of semiconductors. These are artificially engineered periodic materials that can deter propagation at specific wavelengths. These are useful characteristics that can be exploited within antenna designs. Surface waves and back radiation can be strongly suppressed. At the present time, fabrication of devices capable of operation up to 500 GHz is possible.
An issue with active phased array based antenna technology for millimetre wave radar, apart from the cost, is that of heat dissipation. There is generally insufficient space to arrange mixers, LNAs and HPAs between successive antenna elements. This poses a problem for the removal of heat. Active phased array based antennas for millimetre wave radar remains an expensive technology.
EBG antenna
dipole antenna
on wood-pile structures

18. Capability – performance, benefits and applications
I am going to briefly outline the capability of millimetre radar in terms of performance, benefits and applications in defence surveillance

19. Capability – performance, benefits and applications
Small size and weight coupled with rapid scanning and high resolution
in angle and range provide excellent resolution of the surveillance volume
In 1959, the degree of terrain mapping detail from a 70 GHz surveillance radar
(AN/MPS-29) permitted vehicle navigation using data solely derived without
use of optical sensors – the forerunner of collision avoidance radar
4 to 9 km range displayed
30 degree azimuth
0.2 degrees resolution
7.5 m range resolution
The small size, compactness and low weight coupled with rapid scanning and high resolution in angle and range provide excellent resolution of a surveillance volume. As early as 1959, the degree of terrain mapping detail of a ground-based surveillance radar working at 70 GHz, permitted vehicle navigation without optical sensors and indeed was the forerunner of collision avoidance radar.
Ref: Long, Rivers and Butterworth (1960)
Sierra Vista, Arizona, USA

20. Major counter-measure threats
ECM (active) ECM (passive) ESM
Unintentional Chaff Direction Finding (DF)
Mutual interference RAM / signature ELINT receivers
EMI Modification Defence suppression
Intentional (jamming) Foliage / natural cover Anti-radiation missiles (ARM)
Noise Camouflage screens
Deception False targets (confusion)
Decoys (target-like)
Clutter
Rain, snow, hail
Ground
Sea
Atmospheric / contaminants
Fog
Smoke
Dust
The major counter-measure threats to millimetre wave radar are summarised in this slide. Many of these threats are common to contemporary microwave radar systems and I do not intend going over topics that you will already be familiar with from the presentations given earlier.

21. Capability – performance, benefits and applications
Narrow antenna beamwidth / low sidelobes with compact and small aperture
High angular tracking accuracy
Reduced ECM vulnerability
Reduction of multipath and clutter at low elevation angles
Improved multiple target discrimination
Improved non-cooperative target identification (NCTI)
Penetration of some optically opaque materials
Mapping quality resolution
Mmw radar has the inherent advantages to overcome the threats previously outlined. Narrow antenna beamwidth and potentially low sidelobes with well designed antennas are probably the most important features.These make intercept and jamming extremely difficult. High angular tracking accuracy and fine spatial resolution to reduce the effectiveness of clutter and chaff also follow with minimisation of multipath and clutter at low elevation angles. Covert operation, possibly with low propagation overshoot such as near or on high atmospheric attenuation bands offer reduced ECM vulnerability to stand- off intercept and limiting the use of long range surveillance or jamming. More conventional electronic countermeasures (ECCM) such as spread spectrum and frequency agility are more effective due to the availability of large operational bandwidths.
Improved discrimination of multiple targets and non-cooperative target identification (NCTI) is also a result of narrow beamwidth and wide RF bandwidth.
The penetration of some optically opaque materials such as cloth, thin camouflage, brick walls and plasterboard is possible for short range systems.
The quality of an image obtained by a fairly modern 77 GHz radar is illustrated. For comparison, an optical image of the same scene is presented to illustrate the quality obtained from a millimetre wave radar. Details of moving vehicles as well as stationary objects such as signs, bridge and road edges are clearly discernible.
Mapping quality resolution is achievable. The photograph shows the received data from a more recent 77 GHz radar that was mounted behind the registration plate of a vehicle and driven along the M5 motorway. Features such as bridges, signs, kerb edges and other traffic are clearly visible.
77 GHz radar and video based measurements from a traffic scene (circa 1998)

22. Examples of current millimetre wave defence radar systems
EDT-FILA (Brazil) fire-control system 8-40 GHz
Small Fred (Russian Federation and associated states (CIS) ground surveillance GHz
SNAR-10 (CIS) surveillance GHz
TOR (CIS) surface-to-air missile system GHz
Cross Swords (CIS) missile fire control GHz
Gukol-4 (CIS) weather/navigation GHz
Systema (CIS) airborne millimetric surveillance, search and rescue, landing aid 100 GHz
Romeo II (France) obstacle avoidance GHz
EL/M-2221 (Israel) multi-function search, track and guidance/gunnery GHz
ASADS (Netherlands) anti-aircraft gun fire-control 35 GHz
FLYCATCHER Mk2 (Netherlands) dual band I/K band air defence
SPEAR (Netherlands) low level air defence fire-control 35 GHz
LIROD (Netherlands) fire control and surveillance system GHz
STING (Netherlands) fire control GHz
STIR (Netherlands) tracking and illumination GHz
Eagle (Sweden) air defence fire-control GHz
Examples of current millimetre wave defence radar systems are outlined. A combination of ground, sea and air based surveillance systems are listed including fire control, weather/navigation and obstacle avoidance.
Flycatcher Mk2
courtesy of Thales

23. Examples of current millimetre wave defence radar systems
Longbow (US) millimetric 94 GHz fire control
Battlefield Combat Identification Systems BCIS (US) all-weather question-and-answer
battlefield identification system 38 GHz band
AN/SPN-46(V) (US) ship borne precision approach and landing system GHz
AN/APQ-175 (US) airborne multi-mode GHz
Surveilling Miniature Attack Cruise Missile SMACM (US) tri-mode seeker 94 GHz
Airborne Data Acquisition System ADAS (UK) F, I and J bands, 35 GHz and 94 GHz
Maritime Clifftop Radar MCR (UK) F, I and J bands, 35 GHz and 94 GHz
Mobile Instrumented Data Acquisition System MIDAS (UK)
F, I and J bands, 35 GHz and 94 GHz
Type 282 (UK) tracking and ranging for test sites GHz
MARCAL (UK) muzzel velocity GHz
Type 911 (UK) surface to air missile tracking GHz
W800 (UK) ground based surveillance FM-CW radar 77 GHz
TARSIER (UK) ground based surveillance 94 GHz
Further examples of millimetre wave defence radar systems. The majority of millimetre wave systems that couple surveillance with fire control will be noted. The more recent applications include radar modes that provide high resolution data that can be construed as imaging.
W800 radar
courtesy NAVTECH Ltd

24. courtesy of Lockheed Martin/Northrop Grumman
Longbow™ system comprised of 94 GHz fire control radar (FCR)
and “fire-and-forget” HELLFIRE missile system
Fielded on US Army Apache AH-64 and British Army WAH-64 Attack Helicopter
Moving target detection to >8 km range, stationary targets to >6 km range
Target identification (non-cooperative) to class (such as tracked, wheeled etc )
The Longbow™ system is a based upon a 94 GHz fire control radar and the “fire and forget” Hellfire missile system. It is fielded upon the US Army Apache AH-64 and the British Army WAH-64 Attack helicopter. It is typically capable of the detection of stationary targets at ranges in excess of 6 km and moving targets beyond 8 km. Furthermore, it has a non-cooperative target identification (NCTI) capability that can attribute targets to a specific class (such as tracked, wheeled etc). However, it cannot attribute targets to specific types within a class such as 4-wheel all-terrain vehicle rather than 10 tonne Landrover vehicle.
Longbow™ system
courtesy of Lockheed Martin/Northrop Grumman

25. Future Packaging improvements / integrated components (MMICs)
- smaller size, lower weight, lower prime power (SWAP)
- Surface Mount Device (SMD) and flip chip replacing wire bond
• System performance improvements
- higher RF power performance
wider RF bandwidth
- exploitation of ultra wideband (UWB) RF capability
- lower receiver noise
more reliable / wider use of solid state RF sources
Exploitation of new materials, techniques and technologies
- GaN, InP/metamorphic HEMTs
- EBG, metamaterials/ negative refractive index (NRI) materials
- Micro-Systems Technologies (MST)/ RF MEMs / MM MEMs
Validation of computer tools (CAD) and electromagnetic (EM) modelling
for design, measurement and analysis
Gazing into the crystal ball I can see improvements in packaging with more integrated components that will result in size reductions, lower weight and low power consumption. The introduction and use of surface mount devices and flip chips will ultimately replace the wire bond.
System improvements will result from the availability of reliable, higher power RF sources with wider RF bandwidth to permit the exploitation of UWB.
New materials, techniques and processes will be introduced. New semiconductor materials such as GaN may significantly improve mmw amplifiers and also the Gunn diode. Simulations show that GaN can provide twice the frequency and a hundred times the power capability of GaAs Gunn diodes. Practical demonstrations of even a fraction of this would justify the development of GaN Gunn diodes. InP HEMT amplifiers give best noise and power performance at high mmw frequencies. Electronic band gap materials and the validated performance of so-called meta-materials may result in wider use but only where distinct benefits are apparent. This will be judged in terms of whole life costs as well as technical performance. The same is true for micro-system technologies that offer micro-electro-mechanical devices.
The validation of computer tools and electromagnetic modelling is crucial for design, measurement and analysis.

26. Future
• Cost reductions - Enhanced military capability at lower equipment cost .. Is it possible ?
cost reductions are likely with growing uptake of huge civil markets
such as automobile collision warning systems (70-80 GHz)
short range radio links / WLANs and optical communications
availability of large scale COTS manufactured components and sub-systems
radar technology at millimetric/sub-millimetric wavelengths
has been relatively expensive but is now more affordable than ever
• Greater functionality - coherent , fully polarised, multiple beams, beam agility
Dual/multi- frequency detection, tracking, classification sensors (multi-mode)
- microwave / millimetre wave / E-O (IR)
- IFF, Non-Cooperative Target Identification (NCTI)
- Electronic Protection Measures (EPM) ECCM / ESM
- interferometry / polarimetry / polarisation agile modes
- autonomy (knowledge-based, adaptive / Radar Resource Management)
- interoperability ? NEC, high speed missiles ?
Cost reductions to enhance military capability and lower equipment cost are worthwhile goals. It is likely that the huge civil market will drive substantial cost reductions in millimetre wave radar for defence surveillance.
Greater functionality is likely with coherent, fully polarised, multiple beams and beam agility with the possible emergence of electronic scanning. The combination of microwave and millimetre wave radars has already begun but we are likely to see closer integration with E-O (IR) systems and radar modes such as IFF and non-cooperative target identification (NCTI). Future radars will exploit a comprehensive suite of electronic protection measures (EPM) and make full use of the available RF spectrum. Interferometry, polarimetry and polarisation agility will be exploited with increased autonomy by robust control offered by radar resource management. The wider deployment of radar upon the international stage in conjunction with an increasing variety and rapidly evolving communication and sensor systems will necessitate interoperability.

27. W-band surveillance radar
Future
Lightweight surveillance radar
- Uninhabited Air Vehicle (UAV) / Uninhabited Combat Air Vehicle (UCAV)
- UAV (military and civil) collision warning / sense and avoid systems
- Airborne Intercept (AI) / manned combat aircraft
- Long Range Cruise Missile (LRCM)/Air Launched UAV (ALUAV)/
- Intelligence, Surveillance and Reconnaissance (ISR)
provided by loitering munitions / High Altitude Platforms (HAP)
- man-pack infantry portable systems
all-weather surveillance of man-made targets
such as personnel and mortars at low altitude
- submarine periscope systems
- war gas (Sarin, Soman etc) and bio-agent (Anthrax etc)
“See-thru-wall” systems
- dismounted combat within urban environments
- concealed weapon (ceramic / plastic) detection
- substance detection
- detection of Improvised Explosive Devices (IED)
- personnel / passenger bag screening
Finally, here are a few future applications that I envisage we shall see.
The uninhabited air vehicle (UAV) and variants are poised to benefit from the compactness of this approach. Intelligence, surveillance and reconnaissance information can be provided by loitering munitions and high altitude platforms as well as conventional aircraft. Portable systems for deployment with infantry units engaged in dismounted combat can provide all-weather surveillance of man-made targets such as personnel and mortars. Again, the compactness leads to benefits for deployment in submarine periscope systems.
Complex organic molecules such as war gases have a rotational absorption spectrum in the millimetre/submillimetre wave region. The absorption of millimetre waves by war gases can be used to detect the presence of Sarin and Soman. At atmospheric pressure, individual spectral lines overlap due to pressure broadening, but the overall spectrum envelope can still be used to characterise individual gases. Biological warfare agents such as anthrax have characteristic phonon resonances in the THz region. If sufficient power is available, absorption and backscatter could provide a convenient means of sensing wind-driven movements at sufficient range such that effective warning may be given to personnel.
The capability to deploy “see-thru-wall” systems using active millimetre wave radar to penetrate some optically opaque materials for dismounted combat, detection of concealed weapons and bombs is closely allied to the passive millimetre wave. Finally, provided that the many (and varied) RF source technologies currently being developed can provide sufficient power, then defence applications such as surveillance will improve and new applications such as sense and avoid for UAVs, “see-thru-wall” and war gas detection systems will emerge to meet the evolving threats.
W-band surveillance radar
courtesy
Q-Par Angus Ltd

28. Thank you
Tel: +44(0)

29. Questions ?
Tel: +44(0)