IMS2012 presented new advances in oscillator technology

IMS2012 presented new advances in oscillator technology

Every year IMS2012 presents a variety of technical sessions. This year it set a record with 1,225 technical papers, submitted from 49 countries around the world. One of the sessions focused on recent advances in VCO technology. A VCO for quadrature signal generation is summarized below, as well as a dual-band switched-mode resonator oscillator.

A paper titled “Load Independent Bulk-Coupled Low Power Quadrature LC VCO” by Washington State University and Xilinx describes a novel low-voltage bulk-coupled CMOS LC quadrature voltage-controlled oscillator (QVCO) implemented in standard 0.18-µm BiCMOS process.

Quadrature signals are used in modern transceivers, and in the past many methods have been proposed to generate these types of signals. In this paper, quadrature signals were achieved by using injection of output signals of independent complementary LV VCOs into body terminal of each cross-coupled pair. Using a tapped capacitor method, load-independence and lower phase noise were achieved.

The proposed QVCO achieved a measured phase noise of –95.6 dBc/Hz at 50-kHz offset from a 6.26-GHz carrier frequency. Additional results include a total power consumption of 3.2 mW at 1.2-V supply voltage, a phase error of 3.4° between quadrature outputs, and a measure figure-of-merit (FOM) of –192.5 dBc/Hz and a FOMA of –197.7 dBc/Hz, respectively. These results were claimed among the best compared to recently published QVCOs. In addition, the active die area was only 0.3 mm2 .

wrcn_Xilinx_aug201209

Chip micrograph of LC QVCO (active die area in 0.3 mm2 )

Another oscillator-related paper presented by the University of California was “A dual-band oscillator with reconfigurable cavity-backed complementary split-ring resonator.” It described a C-band dual-band oscillator using a reconfigurable cavity-backed complementary split-ring resonator (CSRR), designed using substrate integrated waveguide (SIW) technology.

The resonator consisted of a PIN diode switch and a CSRR resonator embedded in an SIW cavity and was able to offer two different resonate frequencies by selecting different diode modes. In order to match each of the two states, a switchable matching stub was used. The paper showed results that indicated that a low-profile, high-Q, and low-phase-noise frequency-switching oscillator was achieved.

Measured results are shown in the following table: