Arne Øistein Olsen

Thermal constraints for heterostructure barrier varactors

Current research on heterostructure barrier varactors (HBVs) devotes much effort to the generation of very high power levels in the millimeter wave region. One way of increasing the power handling capacity of HBVs is to stack several barriers epitaxially. However, the small device dimensions lead to very high temperatures in the active layers, deteriorating the performance. We have derived analytical expressions and combined those with finite element simulations, and used the results to predict the maximum effective number of barriers for HBVs. The thermal model is also used to compare the peak temperature and power handling capacity of GaAs and InP-based HBVs. It is argued that InP-based devices may be inappropriate for high-power applications due to the poor thermal conductivity of the InGaAs modulation layers.

High power w-band monolithically integrated tripler

We have designed, fabricated and characterized a Heterostructure Barrier Varactor based monolithic tripler at 97 GHz. The original InP host substrate is used as the microstrip waveguide. Measurement results show efficiencies of almost 20% and a maximum output power of 85 mW. Initial comparison with hybrid (flip-chip) solutions imply that the monolithic approach has superior performance.

A 100-GHz HBV frequency quintupler using microstrip elements

A new quintupler concept using a heterostructure barrier varactor has been fabricated and measured. The multiplier consists of a quartz circuit mounted in a full height crossed waveguide block, and hence uses a mixture of waveguide components and microstrip elements. The embedding impedance for the fundamental frequency is provided by tuneable backshorts, whereas conventional microstrip circuit elements are used for impedance matching for the third and fifth harmonic. This topology is highly suitable for monolithic integration, and a peak conversion efficiency of 4.9% was measured at 102.5GHz with an input power of 13dBm.

Heterostructure Barrier Varactor Quintuplers for Terahertz Applications

We present progress and status of heterostructure barrier varactor quintupler sources for 170 GHz and 210 GHz (G-band). The source modules feature an ultra-compact waveguide block design, and a microstrip matching circuit on high-thermal-conductivity AlN to improve the power handling capability. Furthermore, we present progress on design and fabrication of integrated HBV circuits for terahertz applications.

Antipodal finline-to-microstrip transition for operation in the Ka band

An antipodal finline to microstrip transition for operation in the Ka Band (26.5-40 GHz) has been designed and characterised. Back to back transitions fabricated on soft substrates have been measured and simulated to verify their behaviour. Various configurations are implemented and a practical method to improve the design is used.

A broadband heterostructure barrier varactor tripler source

We present the first demonstration of a broadband Heterostructure Barrier Varactor tripler, designed to cover a major part of the WR-8 waveguide band. The source comprises a waveguide housing, a six-barrier InP-HBV diode flip-chip mounted on an AlN microstrip filter circuit. The conversion loss 3-dB bandwidth was measured to 17 % at a center frequency of 112 GHz. The maximum output power was more than 15 mW for an input power of 300 mW. There are no mechanical tuners or DC-bias, which simplifies assembly and allows for ultra-compact design.

High power HBV multipliers for F- and G-band applications

Progress and realisation of applications in the 100-240 GHz region is inhibited by the lack of high-power sources. Therefore, in an effort to reach watts of output power, we have tailored devices, circuits, materials, and design and fabrication methods for improved thermal management and high overall conversion efficiencies.

A low cost fixed tuned F-band HBV frequency tripler

We present a novel fixed tuned heterostructure barrier varactor diode (HBV) tripler. This new multiplier consists of a microstrip section, which provides the critical impedance matching, and the diode, connected to microstrip to waveguide transitions at each end. The circuit is inserted in the E-plane of a waveguide mount, and both the input (Q-band) and the output (F-band) waveguide to microstrip transitions are realized using antipodal finlines. A peak efficiency of 4.2% with a 3% 3-dB bandwidth at 3/spl times/42.6 GHz for an input power of 13 dBm has been measured.

A monolithic 280 GHz HBV frequency tripler

We present the design and measurements of a Heterostructure Barrier Varactor based frequency tripler for 280 GHz. The tripler is fabricated as a monolithic circuit on an InP substrate, including the input and output waveguide probes. Several circuit versions for input power levels between 100 mW and 1W have been designed