Technology Today Volumn 3 Issue 1 - Raytheon

Raytheon
Innovation for Mission Success
RF Technology — A Legacy of Innovation
M
ost of us find science
fiction stories developed
for television and
movies an exciting interlude from
our normal activities — one that
takes us into a make-believe world
of action-adventure, full of thought
provoking insights into what the
future may hold for us.
Of the science-fiction/outer-space epics
shown on TV and in movies, one of the
most ground-breaking was the Star Trek TV
series. This anthology — which told the
story of space exploration in the distant
future — prefigured many astonishing technological
advancements: specifically, the
phaser weapons and photon torpedoes that
protected the ship; the large sensor array
that encased the ship and provided longand
short-range sensor data in the form of
screen displays of nearby planets, gas
clouds, and space ships; the ship’s
ability to remotely monitor atmospheric,
environmental and radiation readings and
to send remote probes into hostile environments
in order to monitor events; the force
field surrounding the ship that protected it
from hostile attacks and harmful environments;
the force fields created within the
ship to isolate and contain alien intruders;
hand-held Tricorders that took local readings
on environmental and health conditions
are among many such precursors.
Those so-called “science-fiction” technologies,
which then seemed impossible, are
today closer than we realize. But what does
Raytheon have to do with these technologies?
The common denominator is that they
all involve RF sensors and signal processing,
very similar to current technologies under
development within Raytheon today.
4
For example, phaser weapons and photon
torpedoes are forms of directed-energy
weapons. The Star Trek Enterprise’s Large
Sensor Array is very similar to our passive
and active array antennas (e.g., F18 AESA,
Ground Based Radars, Space Based Radars,
and EW systems), all of which provide target
tracking and classification along with
ground SAR mapping. Remote sensing of
atmospheric, environmental and radiation
is similarly done by today’s satellite Multispectral
Sensors (some RF and some optical).
The Enterprise’s Remote Probe is similar
to today’s Unmanned Air, Ground and
Water Vehicles. The spaceship’s outer force
field and local containment fields are similar
to today’s electromagnetic containment
fields used in fission reactors or high frequency
microwave weapons, used to cause
enemies discomfort when in the field.
Finally, the Tricorder is similar to miniature
sensors for detecting poisonous gases,
viruses and biological agents under development
today for homeland defense. All
of these “today” technologies are the
forerunners of technologies that some may
have thought didn’t fall within the laws of
Physics. Many other Star Trek technologies
not mentioned here also have sound, nearidentical
facsimiles in today’s technologies,
(though we may have to wait to see if
human bodies can actually be transported
through space at the molecular level).
So, just what is this thing called RF
Technology? RF — short for Radio
Frequency — is defined as any frequency in
the electromagnetic spectrum associated
with radio wave propagation through freespace.
An RF Sensor is an electronic system
that transmits and receives information via
these electromagnetic waves. Thus the term
RF is associated not only with the RF waves
themselves, but also includes other aspects
of RF electromagnetic wave generation and
processing, as well as information coding,
propagation, reflection, detection and, most
importantly, information decoding.
Not all RF waves, however, are propagated
in free space. Other forms of media exist for
electromagnetic propagation, including
copper wires, waveguides, transmission
lines and fiber optics (which are useful in
containing electromagnetic fields in small,
confined regions). Some examples of these
types of RF transmission media include ethernet
and coaxial television cables.
The entire electromagnetic spectrum covers
a range from Direct Current (DC), through
microwaves to visible light — and on up
through X-Rays and Gamma Rays.
VLF 3-30 KHz 100-10 km Very Low
Frequency
LF 30-300 KHz 10-1 km Low Frequency
MF 300 KHz-3 MHz 1 km-100 m Medium
Frequency
HF 3-30 MHz 100-10 m High Frequency
VHF 30-300 MHz 10-1 m Very High
Frequency
UHF 300-3000 MHz 1 m-10 cm Ultra High
Frequency
SHF 3-30 GHz 10-1 cm Super High
Frequency
EHF 30-300 GHz 1 cm-1 mm Extremely High
Frequency
Microwaves
Sub- 300 GHz-3 THz 1mm-0.1 mm Millimeter and
mm sub millimeter
Wave Wavelength
The RF band, occupying the lower frequencies
of the electromagnetic spectrum (from
DC to about 300 GHz), is commonly used
for radio communications, radar detection/
target tracking (although visible light is now
being used for these same purposes) and
remote sensing. (Radar is short for Radio
Detection and Ranging.)
The older classification for RF band frequencies
covered a range of about 10 KHz-1000
MHz, which included radio and television
transmissions, while today’s definition has
expanded to include frequencies from audio