Aha, found it:
Radio spectrum refers to the part of the electromagnetic spectrum corresponding to radio frequencies ¡V that is, frequencies lower than around 300 GHz (or, equivalently, wavelengths longer than about 1 mm).
Different parts of the radio spectrum are used for different radio transmission technologies and applications. Radio spectrum is typically government regulated in developed countries and, in some cases, is sold or licensed to operators of private radio transmission systems (for example, cellular telephone operators or broadcast television stations). Ranges of allocated frequencies are often referred to by their provisioned use (for example, cellular spectrum or television spectrum).
By frequency:
A band is a small section of the spectrum of radio communication frequencies, in which channels are usually used or set aside for the same purpose.
Above 300 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that the atmosphere is effectively opaque, until it becomes transparent again in the near-infrared and optical window frequency ranges.
To prevent interference and allow for efficient use of the radio spectrum, similar services are allocated in bands. For example, broadcasting, mobile radio, or navigation devices, will be allocated in non-overlapping ranges of frequencies.
Each of these bands has a basic bandplan which dictates how it is to be used and shared, to avoid interference and to set protocol for the compatibility of transmitters and receivers.
As a matter of convention, bands are divided at wavelengths of 10n meters, or frequencies of 3¡Ñ10n hertz. For example, 30 MHz or 10 m divides shortwave (lower and longer) from VHF (shorter and higher). These are the parts of the radio spectrum, and not its frequency allocation.
Band name Abbreviation ITU band Frequency
and
wavelength in air Example uses
Tremendously low frequency TLF < 3 Hz
> 100,000 km Natural and man-made electromagnetic noise
Extremely low frequency ELF 3¡V30 Hz
100,000 km ¡V 10,000 km Communication with submarines
Super low frequency SLF 30¡V300 Hz
10,000 km ¡V 1000 km Communication with submarines
Ultra low frequency ULF 300¡V3000 Hz
1000 km ¡V 100 km Submarine communication, Communication within mines
Very low frequency VLF 4 3¡V30 kHz
100 km ¡V 10 km Navigation, time signals, submarine communication, wireless heart rate monitors, geophysics
Low frequency LF 5 30¡V300 kHz
10 km ¡V 1 km Navigation, time signals, AM longwave broadcasting (Europe and parts of Asia), RFID, amateur radio
Medium frequency MF 6 300¡V3000 kHz
1 km ¡V 100 m AM (medium-wave) broadcasts, amateur radio, avalanche beacons
High frequency HF 7 3¡V30 MHz
100 m ¡V 10 m Shortwave broadcasts, citizens' band radio, amateur radio and over-the-horizon aviation communications, RFID, Over-the-horizon radar, Automatic link establishment (ALE) / Near Vertical Incidence Skywave (NVIS) radio communications, Marine and mobile radio telephony
Very high frequency VHF 8 30¡V300 MHz
10 m ¡V 1 m FM, television broadcasts and line-of-sight ground-to-aircraft and aircraft-to-aircraft communications. Land Mobile and Maritime Mobile communications, amateur radio, weather radio
Ultra high frequency UHF 9 300¡V3000 MHz
1 m ¡V 100 mm Television broadcasts, microwave ovens, microwave devices/communications, radio astronomy, mobile phones, wireless LAN, Bluetooth, ZigBee, GPS and two-way radios such as Land Mobile, FRS and GMRS radios, amateur radio
Super high frequency SHF 10 3¡V30 GHz
100 mm ¡V 10 mm Radio astronomy, microwave devices/communications, wireless LAN, most modern radars, communications satellites, satellite television broadcasting, DBS, amateur radio
Extremely high frequency EHF 11 30¡V300 GHz
10 mm ¡V 1 mm Radio astronomy, high-frequency microwave radio relay, microwave remote sensing, amateur radio, directed-energy weapon, millimeter wave scanner
Terahertz or Tremendously high frequency THz or THF 12 300¡V3,000 GHz
1 mm ¡V 100 £gm Terahertz imaging ¡V a potential replacement for X-rays in some medical applications, ultrafast molecular dynamics, condensed-matter physics, terahertz time-domain spectroscopy, terahertz computing/communications, sub-mm remote sensing, amateur radio.
So, Joyce, from the above, different material dielectric properties and design/fabrication rules would be needed for a 1 Ghz circuit as opposed to a 300+ Ghz. This just illustrates that you are absolutely correct; how high is high?
________________________________________
From: Joyce Koo [[log in to unmask]]
Sent: Friday, July 20, 2012 8:32 AM
To: Stadem, Richard D.; TechNet E-Mail Forum
Subject: RE: [TN] Low Loss PCB Material
You never know if he is talking about 5 or 40 or even automotive radar that could be 24 or 77.
Joyce Koo
Materials Researcher - Materials Interconnect Lab
Research In Motion Limited
Office: (519) 888-7465 79945
Mobile: (226) 220-4760
-----Original Message-----
From: Stadem, Richard D. [mailto:[log in to unmask]]
Sent: Friday, July 20, 2012 9:29 AM
To: TechNet E-Mail Forum; Joyce Koo
Subject: RE: [TN] Low Loss PCB Material
High frequency RF is considered to be above 1 ghz, generally speaking. Not sure if this is formalized somewhere?
________________________________________
From: TechNet [[log in to unmask]] On Behalf Of Joyce Koo [[log in to unmask]]
Sent: Friday, July 20, 2012 8:02 AM
To: [log in to unmask]
Subject: Re: [TN] Low Loss PCB Material
How high is "high"?
Joyce Koo
Materials Researcher - Materials Interconnect Lab
Research In Motion Limited
Office: (519) 888-7465 79945
Mobile: (226) 220-4760
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask]
Sent: Friday, July 20, 2012 12:50 AM
To: [log in to unmask]
Subject: Re: [TN] Low Loss PCB Material
Hi Richard,
Thanks a lot. I will check out these materials.
Regards
Ravinder Ajmani
HGST, a Western Digital company
[log in to unmask]
5601 Great Oaks Pkwy.
San Jose, CA 95119-1003
www.hgst.com
"Stadem, Richard D." <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
07/19/2012 06:54 PM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
"Stadem, Richard D." <[log in to unmask]>
To
<[log in to unmask]>
cc
Subject
Re: [TN] Low Loss PCB Material
Hi, Ravinder
You might want to look at the following:
Nelco N4000-13EP
Panasonic Megtron Getek
Taconic RF-35TC or RF35A2
I know these are all RF-tailored, but not sure if all are halogen free. I
know the Taconic materials are.
You would need to check with them about the UL approval rating.
________________________________________
From: TechNet [[log in to unmask]] On Behalf Of [log in to unmask]
[[log in to unmask]]
Sent: Thursday, July 19, 2012 8:10 PM
To: [log in to unmask]
Subject: [TN] Low Loss PCB Material
Hi All,
We discussed with our quick-turn fab the use of low-loss PCB materials for
high-speed applications. As per the discussions,the only such material
that is Halogen-Free and has UL Approval seems to be Rogers Theta
material. If there are other materials available in US and more
importantly at the high-volume fabs off-shore then please share the
information. I will really appreciate it.
Thanks.
Regards
Ravinder Ajmani
HGST, a Western Digital company
[log in to unmask]
5601 Great Oaks Pkwy.
San Jose, CA 95119-1003
www.hgst.com
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