March 2008 Project: IEEE P802.15 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: 503-712-5012 E-Mail: richard.d.roberts@intel.com Re: Abstract: Explores some THz link budget issues Purpose: Informative Notice: This document has been prepared to assist the IEEE P802.15. 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 P802.15. R. Roberts. Intel

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

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

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

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

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

March 2008 Thanks! R. Roberts. Intel