Equivalent circuits have been derived for microstrip ring and varactor-tuned ring resonators. It was found that the resonant frequency is slightly lower as the coupling gap becomes smaller. Varactor-tuned ring resonators have been developed with up to 15 percent tuning bandwidth using packaged varactor diodes. A dielectrically loaded microstrip ring circuit with lower loss was demonstrated. The results should have many applications in electronically tunable oscillators and filters in both hybrid and monolithic integrated circuits.

On the Study of Microstrip Ring and Varactor-Tuned Ring Circuits

A novel millimetre-wave integrated circuit Gunn voltagecontrolled oscillator (VCO) has been developed with high output power using suspended stripline. An output power of 100 to 150mW has been achieved at frequencies between 33 and 42 GHz. A varactor diode was mounted in alignment and in close proximity to the Gunn diode to achieve an electronic tuning range of 300 MHz

High-performance millimetre-wave suspended stripline Gunn VCO

Many receivers operating at millimetre wavelengths utilise a frequency downconverter as their first stage. A rugged, low-conversion loss and simplified cross-bar mixer operating at the atmospheric window centered at 33 GHz was designed, developed and tested as a forerunner to mixers operating at atmospheric windows centred at higher frequencies. The cross-bar mixer exhibits a conversion loss of less than 5 dB over a bandwidth of 2 GHz. Design and optimisation procedures of the mixer are outlined.

The development of a simplified cross-bar mixer operating at Ka-band

A 40-60-GHz-band integrated circuit dielectric resonator oscillator (DRO) in suspended stripline (SSL) is described. This Gunn DRO provides an output power of more than 17 dBm, and a mechanical tuning range of 1.5 GHz at 54 GHz has been obtained. A varactor-controlled oscillator (VCO) with an output power of 15 dBm across its 1000-MHz electronic tuning bandwidth at 53 GHz is also reported. >

U-band shield suspended-stripline (SSL) Gunn DRO and VCO

A millimeter-wave IC dielectric resonator oscillator (DRO) is proposed. Equations that give the resonant frequency of the dielectric resonator DR in suspended stripline (SSL) are derived. A U-band voltage-controlled oscillator (VCO) with varactor tuning also has been developed. The Gunn diode and varactor used in both of the oscillators are commercially available packaged devices. Restrictions on the performance of the oscillators imposed by packaged and mounted networks and the self-characteristics of the solid-state devices have been analyzed. An electronic tuning range greater than 1000 MHz with an output power exceeding 15 dBm across the bandwidth in the 53-GHz region has been realized for the SSL VCO. An SSL DRO with an output power of more than 17 dBm and a mechanical tuning range of 1.5 GHz in the 54-GHz region has been achieved. >

U-band shield suspended-stripline Gunn DRO and VCO

The miniature millimeter-wave integrated circuit LO/mixer assembly was developed with over the full waveguide band coverage and good temperature stability. A conversion loss of less than 7 dB was achieved over 16 GHz instantaneous IF frequency with the RF swept from 30 to 46 GHz and the LO at 48 GHz. With another mixer, when the RF was swept from 18 to 30 GHz and the LO was at 32 GHz, similar results were achieved. Using resonant stub and dielectric temperature compensation produced good temperature stability.

Miniature Millimeter-Wave Integrated Circuit Wideband Downconverters

Various microstrip components, including mixers, IMPATT oscillators, Gunn oscillators, doublers, and circulators, have been developed at W-band with state-of-the-art performance. The use of microstrip drastically reduces fabrication costs due to the less stringent machining tolerance. The design and performance of these components will be reported.

R.S. Tahim

Papers

Miniature Millimeter-Wave Integrated Circuit Wideband Downconverters

W-Band (75 to 110 GHz) Microstrip Components