A highly compact 2.4-GHz passive 6-bit phase shifter with ambidextrous quadrant selector

An extremely compact architecture for a passive 6-bit digital phase shifter is presented. The phase shifter has a range of 360° with 5.6° resolution at 2.4 GHz. The architecture is composed of an ambidextrous quadrant selector in series with a digital fine-tuned phase shifter that makes use of high-ratio symmetrical digitally variable capacitors loading a lumped element transmission line. The phase shifter achieves a 50 Ω match in all 64 states. The circuit occupies approximately 0.47 mm2 on die, and the entire test chip measured 0.84 mm2, including bond pads and ESD structures. The 1-dB compression point was +23 dBm. The chip was fabricated in a commercial 0.13- μm silicon-on-insulator CMOS process

A Novel Retro-directive Phased Array Antenna Architecture

Mobile wireless communication scenarios can range from a simple indoor WiFi link to a satellite internet connection to an airplane. Virtually in all scenarios, dynamic changes in the propagation environment or the movement of transmitter and receiver are inevitable. Therefore, the wireless link often experiences quality degradation or even interruption. Adaptive antenna arrays offer a promising solution to combat wireless channel impairments as they adaptively reshape their radiation pattern. For two-way communication, an antenna should be retro-directive meaning its transmit and receive beams are aligned. To achieve retro-directivity, techniques based on direction-of-arrival and self-phasing can be used. The former usually calls for a complex calibration routine to estimate the direction of arrival and beamsteering; the latter relies on the received signal to generate the transmit beam, imposing several limitations on its adaptability. In this thesis, a novel retro-directive phased array architecture is proposed that does not require calibration and which generates its transmit wave independently of its receive wave. Moreover, its radiation pattern can be adaptively shaped by a simple beamforming algorithm, while its transmitted and received beams remain aligned. Structurally, it is comprised of independent modules that can be placed in virtually any arrangement without any hardware modification. The architecture uses the LO phase-shifting technique to steer its beams. The LO signals are generated with a novel frequency synthesizer; it creates a pair of LO signals for the transmission and reception paths to achieve retro-directivity. The proposed antenna architecture is demonstrated practically using a 10-element prototype, verifying its ability to steer the transmit and receive beams while keeping them aligned. In addition, two of the key circuit components of the LO synthesizer, a fractional frequency divider and a novel phase-conjugating phase shifter, are designed and successfully implemented on 65nm CMOS technology, paving the path for use in future applications