Stefan Humbla

Ceramic Microwave Circuits for Satellite Communication

KERAMIS is the acronym of a German research and development project funded by the German Space Agency (DLR) and the Federal Ministry of Economics and Technology (BMWI). The consortium is developing an RF circuit technology for Ka band multimedia satellite applications. A set of modules has been designed, manufactured, and tested by the partners of the consortium. The goal of this effort is to qualify the KERAMIS technology for space applications and to participate in an on-orbit-verification (OOV) program of the DLR. The launch of the technology verification satellite (TET) is scheduled for late 2010. This paper will give an overview of innovative circuit and module designs as well as the assembly, integration, and test results of the project. The authors will present a modular circuit concept for state-of-the-art transmitters and receivers in space at around 20 GHz. Selected modules are a 4 × 4 switch matrix, two synthesizers, and other RF modules. All circuits are based on multilayer ceramic (LTCC) incl...

Tunable Dual-Band Microwave Devices based on a Combination of Left/Right-Handed Transmission Lines

Metamaterial transmission lines can be realized as a combination of transmission line sections with positive and negative dispersion. Such lines, which are also known as right- and left-handed transmission lines, exhibit different dispersion characteristics. Compared to homogeneous networks, the use of cascaded line sections gives additional degrees of freedom for improving the performance of microwave devices. For the design process, LC-equivalents of the right- and left-handed transmission line sections are used. This facilitates the consideration of tunable capacitors, e.g., varactor diodes, to provide frequency tuning of the devices. At the same time, the geometrical dimensions of the devices can be drastically reduced. This paper presents the results of simulation and experimental investigation of a miniature rat-race-ring and a dual-band filter free of spurious response, both manufactured as fully-integrated ceramic multilayer modules based on Low-Temperature Co-fired Ceramics. The design of tunable versions of these devices is also discussed.

Fine-line structuring of microwave components on LTCC substrates

Low Temperature Co-fired Ceramics (LTCC) are used in a wide range of RF and microwave applications. The ceramic multilayer technology provides a truly three-dimensional circuit technology, hermetical sealing, hybrid integration, and favorable microwave properties at moderate costs. In order to take advantage of high frequencies with guided wavelengths of the order of millimeters, a precision of lines and spaces better than the resolution of 50 µm available with standard patterning methods is crucial.

On-Orbit Verification of a 4×4 switch matrix for space applications based on the low temperature co-fired ceramics technology

Abstract We have developed a compact, high-performance, mechanically robust reconfigurable microwave switch matrix as well as peripheral components such as diode driver, voltage controlled oscillator, and power detector modules for satellite applications using the low temperature co-fired ceramics technology (LTCC) and hybrid integration of integrated circuits. In order to verify the technology for space applications, we combined these components to build a system that enables automated verification of the switch matrix in space, accounting for power consumption, mass, overall geometrical dimensions, and mechanical robustness. The system passed a full space qualification. During a one year On-Orbit-Verification (OOV) mission aboard the German test satellite TET-1 (technology evaluation carrier) launched on July 22, 2012, the correct operation and reliability of the entire switch matrix system and thereby the used technology will be demonstrated.

Tunable microwave devices based on left/right-handed transmission line sections in multilayer implementation

Metamaterial transmission lines can be realized as a combination of right- and left-handed transmission line (TL) sections exhibiting positive and negative dispersion. This approach gives additional degrees of freedom for improving the performance of microwave devices. Artificial right- and left-handed sections, which are based on lumped-element unit cells consisting of inductance and capacitances (LC-cells), are used. This makes it possible to decrease dimensions of the devices drastically. Furthermore, using variable capacitors in LC-cells allows designing tunable devices. This paper presents the results of design, numerical simulation, and experimental investigation of a tunable rat-race ring and free-of-spurious response dual-band filter manufactured as integrated ceramic multilayer circuits based on low-temperature co-fired ceramics. Commercial semiconductor varactors have been used as tunable components.

180° Power Dividers Using Metamaterial Transmission Lines

Application of metamaterial left-handed transmission lines to design 180deg power dividers is considered. Design of microstrip and coplanar miniaturized rat-race rings based on artificial left-handed and right-handed transmission line sections is presented. The devices have been implemented as quasi-lumped-element multilayer structures on low-temperature co-fired ceramics. Novel broadband Wilkinson-type 180deg power dividers using metamaterial left-handed transmission lines are proposed.

Multi-band and tunable multi-band microwave resonators and filters based on cascaded left/right-handed transmission line sections

Design of microwave devices based on a combination of traditional right-handed transmission line sections with positive dispersion and metamaterial left-handed transmission line sections with negative dispersion is considered. Compared to homogeneous transmission lines, the use of cascaded line sections gives additional degrees of freedom for the design of microwave devices with enlarged functionality and unique performance. Artificial right- and left-handed transmission lines based on lumped-element equivalent cells help to minimize the dimensions of microwave devices. For filters, a combination of cascaded right- and left-handed transmission lines can be applied advantageously, to control the position and the widths of the individual pass-bands and the parasitic response of higher harmonics. This paper describes the theoretical approach to the design of multi-band resonators and filters with highly suppressed response of higher harmonics. Selected devices were manufactured as three-dimensional ceramic multilayer modules based on low-temperature co-fired ceramic technology. The results of numerical simulation and experimental investigation of these devices are compared. Furthermore, the employment of variable capacitors in single cells of artificial transmission lines provides frequency tuning of the devices. The design of tunable dual-band filters is discussed, and the experimental results are presented.

Efficient Design of Multilayer Microwave Modules using an Element-Wise Simulation Technique

A technique for the fast and efficient modeling of complex microwave modules is investigated. In order to reduce simulation and optimisation time of spatially extended transmission line structures, a library of basic microwave components together with an approach for the decomposition and cascaded simulation of extended microwave circuits is proposed. To verify the design method, simple test structures as well as constituents of challenging low temperature co-fired ceramics (LTCC) modules from an ongoing R& D project are analysed and evaluated. The promising results encourage further efforts to exploit the discussed method for automated design approaches.

Novel Wilkinson-Type Power Dividers Based on Metamaterial Transmission Lines

This paper focuses on applications of the metamaterial left-handed transmission lines to the design of novel Wilkinson-type power dividers. Novel configurations of broadband 180deg Wilkinson power dividers suitable for practical implementation are proposed. A concept of designing dual-band Wilkinson power dividers based on a combination of right-handed and left-handed transmission line sections is considered as well. A band broadening technique for the dual-band Wilkinson power dividers is discussed.

A package-level implementation of traveling-wave switch using PIN-diodes

A single-pole single-throw switch constituting the transparent path in a reconfigurable switch matrix is presented, improving the availability of the switch matrix in case of an on-board power-fail. The design of the switch is based on the traveling-wave concept using packaged PIN-diodes on a thick-film ceramic substrate under the constraints on the number of PIN-diodes and power dissipation. The circuit design and analysis of the switch based on the concept of an artificial transmissionline are described. Unlike the traditional low-pass characteristics inherent to traveling-wave switches, high isolation is achieved by transforming the parasites of the PIN-diodes in the shunt arms to reveal band-pass characteristics besides assisting the assembly of the package. On-wafer measurements reveal an isolation ≥ 45 dB and an insertion loss ≤ 6 dB in the Ka-band downlink frequencies (17...22 GHz).