Timo Tick

Design and measurement data for a microwave CP antenna using a new travelling-wave feed concept

In this paper, we propose a new technique, which is capable of yielding high quality circular polarization, with a feeding system that is particularly suitable for incorporating in multilayer microwave circuits. This type of circuit can be fabricated either in thick-film or LTCC, which are attractive because they can provide a combination of high-performance and low-cost fabrication.

Low-Sintering-Temperature Ferroelectric-Thick Films: RF Properties and an Application in a Frequency-Tunable Folded Slot Antenna

This investigation is one of the first steps toward the realization of low-cost, mass-producible, tunable antenna applications utilizing an integrated ferroelectric-thick film made of bariumstrontiumtitanate material. The dielectric properties of the electric-field-adjustable fired BST thick film are presented in the frequency range of 16 GHz. The key advantages of the material are high tunability (25% with 2.5 V/mum), compatibility with silver electrodes, and the ability to produce film thicknesses down to 25 mum. The utilization of the material is demonstrated by tuning the operating frequency of a folded slot antenna with an integrated variable capacitor. In addition, the impact of tuning on the antennas total efficiency and radiation pattern is experimentally studied through a comparison with the performance of a reference antenna not incorporating the varactor.

Design and measurement data for a microwave dual-CP antenna using a new traveling-wave feed concept

Design and measurement data are presented that show how the novel concept of a traveling-wave-fed circular-polarization (CP) microstrip antenna can be extended to provide an antenna with dual CP. A new refinement to the basic antenna structure is also introduced that shows that the efficiency of radiation can be enhanced by using a dual dielectric to improve the fringing fields at the edges of the radiating patches by around 40%. Furthermore, new theoretical and simulated data are introduced to support the original traveling-wave feed concept

Right/left-handed transmission line LTCC directional couplers

Using a combination of right-handed and left-handed transmission lines to design of miniaturized directional couplers (DC) is considered. Design of miniaturized 3-dB and 10-dB quadrature DC and a rat-race hybrid for wireless applications is presented. Design of a dual-band 3-dB DC is reported as well. All the DCs have been designed as fully-integrated multilayer LTCC structures containing no SMD components.

Design and investigation of miniaturized high-performance LTCC filters for wireless communications

This paper presents design and investigation of three miniaturized high-performance bandpass filters for wireless applications at 2.45 GHz. The quasi-lumped-element filters with improved insertion loss performance and reduced size, have been designed on a commercial low-temperature co-fired ceramics (LTCC) system, manufactured and experimentally investigated.

Integrated air-filled waveguide antennas in LTCC for G-band operation

In this paper, a new concept in planar transmission lines is introduced, namely the air-filled substrate integrated waveguide. The air-filled guide was fabricated within an LTCC planar circuit. Measurements were made over G-band (140GHz-220GHz) which showed the integrated guide had insertion losses comparable, or slightly less, than other planar transmission lines at these frequencies. To further demonstrate the potential of the new structure a 150GHz slot antenna, using integrated air-filled waveguide, was designed and tested. The principal significance of the new integration technology proposed here is that it will permit the integration of air-filled, high-Q cavity filters and allow the closed integration of efficient slot antennas with front-end circuitry.

In-Band Frequency-Tunable Ceramic Planar Inverted-F Antenna (PIFA) Utilizing an Integrated BST-Based Variable Capacitor

The dielectric properties of low-sintering-temperature (LTCC) Barium Strontium Titanate (BST) thick film paste at high frequencies (0.8–5 GHz) are briefly presented. The utility of the BST paste was demonstrated by tuning the resonance frequency of a ceramic PIFA for mobile terminals operating at 2 GHz. The frequency tuning achieved can be used to compensate frequency detuning caused by the proximity of the user to the antenna. The impact of tuning on the antennas total efficiency and radiation pattern was experimentally studied through a comparison with the performance of a reference antenna not incorporating the varactor.

An X-Ray Imaging-Based Layer Alignment and Tape Deformation Inspection System for Multilayer Ceramic Circuit Boards

Advances in conductor patterning and via preparation techniques have facilitated a continuous increase in the circuit packaging density of ceramic multilayer substrates. A decrease in feature size combined with the trend toward constantly increasing the processed panel size is placing extremely high demands for layer-to-layer alignment as well as ceramic green tape stability. This paper describes the main mechanisms contributing to layer-to-layer alignment errors in the ceramic tape alignment and stacking process and introduces a simple, nondestructive, X-ray imaging-based method for measuring alignment error in a ceramic multilayer substrate. A low-temperature cofired ceramic (LTCC) test panel was manufactured and analyzed using the introduced X-ray inspection method. In order to define the error caused by tape alignment and stacking as well as tape deformation, the alignment error between the layers was calculated over the whole panel area. The specific area of an LTCC panel that meets the required alignment tolerances can be identified from the calculated results.