Timo J. Tolmunen

An efficient Schottky-varactor frequency multiplier at millimeter waves. Part II: Tripler

The efficiency of millimeter wave doublers with a wide tunable bandwidth was studied. The efficiency depends on the varactor parameters and the embedding impedances seen by the diode at fundamental and harmonic frequencies. Millimeter wave doublers were simulated with a nonlinear analysis program to find optimum embedding impedances for a given diode. Also the sensitivity of the efficiency to various diode and circuit parameters was evaluated. A scaled model was constructed in order to experimentally optimize the impedances. For experimental verification a doubler from 40–58 GHz to 80–116 GHz was constructed. The highest efficiency measured was 45% at 94 GHz with 5 mW input power. The highest efficiency obtained with 20 mW input power was 38%.

A single barrier varactor quintupler at 170 GHz

InGaAs-InAlAs single-barrier varactor (SBV) diodes are tested as frequency quintuplers. The diodes were tested in a crossed-waveguide structure and provided output frequencies between 148 and 187 GHz. The highest observed flange-to-flange efficiency was 0.78% at an output frequency of 172 GHz. This is nearly four times greater than the best quintupler efficiency obtained for previous SBV varactors made from the GaAs-AlGaAs materials system. >

Comparison of Higher-Order Multipliers to Cascaded Doublers and Triplers in Submillimeter Signal Generation

A theoretical study using a full nonlinear analysis has been carried out on the feasibility of producing local oscillator power at frequencies 300-600 GHz by using Schottky-diode frequency multipliers. Solid state local oscillators are needed for space born radiotelescopes planned for operation in the beginning of the next century. A comparison has been made between the efficiencies of higher-order multipliers and cascaded doublers and triplers. In order to get experimental background for those theoretical studies a quadrupler for 140 GHz, a quintupler for 170 GHz and a doubler for 180 GHz were analyzed both theoretically and experimentally.

Higher order frequency multipliers-a solution for MM- and subMM-wave local oscillator signal generation

A frequency quadrupler for 140 GHz and frequency doublers for 183 GHz and 230 GHz have been analyzed both theoretically and experimentally. The generation of a 345-GHz signal using a doubler, tripler, quadrupler, or two cascaded doublers and the generation of a 460-GHz signal using a doubler, quadrupler, or two cascaded doublers have been theoretically compared. It is found that if tube oscillators are available at 170-230 GHz, the best choice for producing 345 or 460 GHz signals is a doubler. This is due to its relative simplicity, which allows a wider operational range in comparison to higher order multipliers. However, if an all-solid-state source is required, a higher order multiplier is often a more reasonable choice.<<ETX>>

Development Of High Efficiency Frequency Multipliers For 130-350 GHz

In this research the feasibility of developing high efficiency mm-wave multipliers in the frequency range of 130-350 GHz has been studied. A frequency quadrupler for 140 GHz, frequency doublers for 183 GHz and 230 GHz and a frequency tripler for 345 GHz have been analyzed and optimized. The development of high efficiency frequency multipliers is especially important for the spaceborne mm-wave and submm-wave heterodyne receivers used for radio astronomy and remote sensing of the atmosphere.

Efficiency Versus Embedding Impedance Of Millimeter Wave Schottky-Varactor Multipliers

The efficiency of a frequency multiplier depends on the varactor parameters and the embedding impedances seen by the diode at fundamental and harmonic frequencies. In this study mm-wave doublers and other multipliers were simulated by computer to find optimum embedding impedances for a given diode. A scaled model was constructed in order to search for optimum impedances for broadband multipliers in practice.

Multiplicateurs de fréquence à varactor de schottky à rendement élevé pour 100 à 1 000 Ghz

There is a strong need of all-solid-state local oscillators in the frequency range of 100 to 1000 GHz, especially for space-borne radio astronomy and remote sensing of the atmosphere. Only up to 150 GHz the need can be satisfied with fundamental solid-state sources such as Gunn oscillators. At higher frequencies multipliers are needed. This paper discusses the Schottky-varactor multiplier theory and its use for design and optimization of millimeter and submillimeter frequency multipliers. Experimental work is also reviewed.RésuméIl existe une demande croissante d’oscillateurs locaux à l’étal solide dans le domaine de fréquence de 100 à 1 000 GHz, spécialement pour la radioastronomie embarquée et en télédétection dans l’atmosphère. La demande peut être satisfaite à l’aide de sources à l’état solide, telles que les oscillateurs de Gunn, uniquement jusqu’à 150 GHz. Aux fréquences supérieures, les multiplicateurs de fréquence sont indispensables. On discute de la théorie des multiplicateurs à varactor de Schottky et de son utilisation pour la conception et l’optimisation de multiplicateurs de fréquences d’ondes millimétriques ou submillimétriques. Les travaux expérimentaux sont également passés en revue.

Analysis and Design of 130-250 GHz Frequency Multipliers

In this research the feasibility of developing high efficiency mm-wave multipliers in the frequency range of 130-250 GBz has been studied. A frequency quadrupler for 140 GBz and frequency doublers for 183 GBz and 230 GBz have been analyzed and optimized. The development of high efficiency frequency multipliers is especially important for the spaceborne mm-wave and submm-wave heterodyne receivers used for radio astronomy and remote sensing of the atmosphere.

A Millimeter Wave Schottky-Varactor Doubler with a Wide Tunable Frequency Range

The efficiency of mm-wave doublers with a wide tunable frequency range was studied. The efficiency depends on the varactor parameters and the embedding impedances seen by the diode at fundamental and harmonic frequencies. Mm-wave doublers were simulated with a computer to find optimum embedding impedances for a given diode. A scaled model was constructed in order to search for optimum impedances for wide-band doublers in practice. For experimental verification a doubler from 40-60 GHz to 80-120 GHz was constructed. An efficiency > 30 % was obtained at the output frequency range from 75 to 96 GHz at various input power levels between 2 and 20 mW. The highest efficiency measured was 42 % at 88.6 GHz with 10 mW input power.