STEERABLE, HIGH-GAIN antennas may be used to overcome limitations of non-line-of-sight (NLOS) communications in the millimeter-wave range. For example, an integrated phased-array transmitter has been developed that supports multi-Gigabit-persecond NLOS 60-GHz links and is compliant with IEEE 802.15.3c. This transmitter, which is integrated in a 0.12-m silicon-germanium (SiGe) BiCMOS process, is the work of Alberto Valdes-Garcia, Arun Natarajan, Scott K. Reynolds, Dong G. Kam, and Duixian Liu from IBM's T.J. Watson Research Center together with Brian Floyd from North Carolina State University and MediaTek's Sean T. Nicolson, Jie-Wei Lai, Ping-Yu Chen, and Jing-Hong Conan Zhan.
The 44-mm2 transmitter comprises an upconversion core followed by a 1:16 power-distribution tree, 16 phase-shifting front ends, and a digital control unit. At 60.48 GHz, it delivers +9 to +13.5 dBm output power per element at 1-dB compression while consuming 3.8 to 6.2 W. Each element achieves a phase-shifting range beyond 360 deg. with amplitude variation below 1 dB across phase settings and adjacent elements.
Beam steering and spatial power combining have been demonstrated with a packaged integrated circuit (IC). See "A Fully Integrated 16-Element Phased-Array Transmitter in SiGe BiCMOS for 60-GHz Communications," IEEE Journal Of Solid-State Circuits, Dec. 2010, p. 2757.