1. March 2008
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: Link Budget Exploration for THz Communications
Date Submitted: 4 March 2008
Source: Rick Roberts, Intel
Address
Voice:
Re:
Abstract: Explores some THz link budget issues
Purpose: Informative
Notice: This document has been prepared to assist the IEEE P It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P
R. Roberts. Intel

2. March 2008
Terahertz Waves for Communications and Sensing
Michael J. Fitch and Robert Osiander
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 25, NUMBER 4 (2004)
Pages 348 to 355
R. Roberts. Intel

3. 1 steradian beam, TX radiation intensity is 1 mW/sr
March 2008
Link Budget – small lens example
C/No is determined as RX sensitivity divided by the sensitivity measurement bandwidth (but is this correct?)
1 steradian beam, TX radiation intensity is 1 mW/sr
Beam area at distance D is D2. Power Density at distance D is 1mW/ D2. Aperture loss for this example is 25x10-6/ D2.
distance D
 =1 sr
THz
Source
THz
Sink
Integrated Power: 1 mW
25 mm sq. RX aperture
R. Roberts. Intel

4. March 2008
Message is that Terahertz has the potential to deliver multi-gigabits at WPAN distances.
Illustrative Example
Link budget example (line-of-sight)
TX radiation intensity: 1 mW/steradian
RX detector sensitivity: 1 pW (assumed measured in 1 MHz)
Excess Atten per meter: 0.1 dB
Terahertz Waves for Communications and Sensing
Michael J. Fitch and Robert Osiander
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 25, NUMBER 4 (2004)
Pages 348 to 355
R. Roberts. Intel

5. March 2008
Reference:
Johnson–Nyquist noise
From Wikipedia, the free encyclopedia
Traditional Noise Figure concept applicable to about 1 THz, and above that it is pessimistic.
R. Roberts. Intel

6. But there are lingering questions … 1. What are realistic TX powers?
March 2008
But there are lingering questions …
1. What are realistic TX powers?
2. What are realistic RX sensitivities and how do we define it?
3. How do we define the noise floor of a THz detect?
How do we calculate NO?
R. Roberts. Intel

7. March 2008
Thanks!
R. Roberts. Intel