D. Kother

A comprehensive evaluation of quasi-static 3D-FD calculations for more than 14 CPW structures-lines, discontinuities and lumped elements

This paper reports on the on wafer evaluation up to 67 GHz of a complete library of coplanar elements for application in MMIC design. The elements under consideration were fabricated on GaAs and simulated utilising a quasi-static 3D-FD tool and measured by a state-of-the-art measurement system. This library covers the range from transmission lines over discontinuities/junctions to lumped elements like inductors, resistors (TFR) and capacitors (MIM). Transmission line effects of TFRs with high DC values and MIMs with relative large geometries are also discussed in this paper.<<ETX>>

MMIC Wilkinson couplers for frequencies up to 110 GHz

Reciprocal power splitters and combiners can be realized by using Wilkinson couplers. However, for frequencies lower than a few GHz such couplers are normally too large for application in MMICs. At the same time, for designing Wilkinson couplers at high frequencies discontinuities must be considered. For the first time, this paper reports on miniaturized Wilkinson couplers for 1.8 GHz with space requirements of 1.2/spl times/0.8 mm/sup 2/ as well as on designing couplers for frequencies up to 80 GHz.<<ETX>>

New types of MMIC circulators

Circulators can be used to separate transmit/receive (T/R) signals and for two-port tuners. Conventional ferrite devices are not applicable for MMICs. Two new types of electronic circulators are presented in this paper covering the frequency range from 1.8 GHz up to 80 GHz.<<ETX>>Circulators can be used to separate transmit/receive (T/R) signals and for two-port tuners. Conventional ferrite devices are not applicable for MMICs. Two new types of electronic circulators are presented in this paper covering the frequency range from 1.8 GHz up to 80 GHz.<<ETX>>

A 100-femtosecond electron beam blanking system

Abstract Conventional electron beam blanking system show the drawbacks of a fixed electron energy, a fixed repetition rate or even unsuitability for repetition rates in the GHz region. This paper describes the development of an ultrafast electron beam blanking system, intended for testing microwave integrated circuits with very high temporal resolution. 100fs electron pulses can be generated with repetition rates in the range from 8 to 18 GHz.

Active CPW MMIC Circulator for the 40 GHZ Band

For the first time, several active coplanar circulators have been designed and fabricated for the 40 GHz band. The technology for these circuits is the PM-HFET technology from Daimler Benz in Ulm. The introduced designs utilize the new CPW model library in the CAD package LIBRA. The return loss of the electronic circulator is better than ¿15 dB and the insertion loss is typically ¿3 dB for a bandwidth of about 6 GHz at a center frequency of 40 GHz. The isolation between the ports is better than ¿20 dB in the frequency band. New designs on InP and GaAs have been made for frequencies up to 80 GHz.

Development of a Coupler in Finline Technique

Among other components directional couplers are employed in millimeterwave finline circuits. The method presented here allows a simple calculation of all modes which can exist on such couplers under consideration of the thickness of the metallization. In this way a 3-dB coupler has been developed for the Ka-band. Numerical and experimental results illustrate the applicability of this method.

A Field Theoretical Analysis of Ferrite-Loaded Image Line Isolators for the Ka-Band

A ferrite isolator in image line technique is investigated both theoretically and experimentally. The used theoretical analysis method allows an exact description of the electromagnetic field in a multilayered structure. The feasibility of a dielectric image line field displacement isolator for the Ka-band is demonstrated.

Enhancement of Coplanar Capacitor Models and Verification Up to 67GHz for (M) MIC Circuit Design

The IMST has recently built up a library with recently more than 18 coplanar elements for CAD applications (2), (3). The theory of the parametric models is based on a quasi static 3D Finite Difference formulation (1). Naghed also introduced in (1) the model of a coplanar interdigital capacitor and presented the verification of this element up to 25GHz. Beyond 40GHz and for long fingers these simulation results diverge from measured data. This paper will report on the enhanced coplanar IDC model and 2 new types of coplanar capacitors - a serial and a parallel MIM capacitor, where line effects are taken into account. The equivalent circuit elements are determined in units per length. The simulated results will be compared with measured data from test circuits on a GaAs wafer up to 67GHz. Parts of these activities are supported by the European Community within the ESPRIT CLASSIC project.

A Combined Measurement Stand for Linear, Nonlinear and Noise Measurements of Microwave Devices and Circuits

A novel approach is presented for a measurement system which is able to investigate the most relevant specifications of microwave circuits and components. The test stand is configured for on wafer measurements up to 60GHz, but can also be used for connectorized device measurements. The main measurement capabilities of the system are: Two and three port scattering parameters, noise figure and noise parameters of two port devices, power and gain measurements including harmonic power and harmonic impedances, all mixer parameters including conversion noise, active load pulling and the spectrum and phase noise of oscillators. Furthermore, a new calibration method has been developed which allows the measurement of absolute values of all power waves at the device under test without frequency converting standards. The system operates in combination with an automatic wafer probing system. The control software for the prober can be integrated in the measurement system software giving the capability of performing wafer mapping of MMICs.

MMIC circulators covering the frequency range from L- to W-band

A new type of circulators is presented which has been tested using circuits covering the frequency range from L- to W-band. This is, for the first time, a principle suitable for applications at 1.8 GHz as well as 77 GHz. At the lower frequencies ferrite drop-in circulators in microstrip technique have been used in the past, while at the upper frequencies the usage of circulators has not been established yet. The measurement result presented here demonstrate the applicability of the new concept.