Patric Heide

Wireless local positioning

Local positioning will be one of the most exciting features of the next generation of wireless systems. Completely new concepts and features for wireless data transmission and transponder systems will emerge. Self-organizing sensor networks, ubiquitous computing, location sensitive billing, context dependent information services, tracking and guiding are only some of the numerous possible application areas. This article introduces different concepts of several existing and emerging systems and applications.

Design, fabrication, and application of precise SAW delay lines used in an FMCW radar system

An inexpensive frequency-modulated continuous-wave (FMCW) radar system is presented in this paper, which, nevertheless, meets all industrial requirements. The FMCW radar uses a low-cost nonlinear voltage-controlled oscillator (VCO), operating at an IF of 2.45 GHz to generate the frequency modulation of the radar system. This VCO signal is applied twice, first to generate the radar transmitter signal at 24 GHz, and then it is fed to a surface acoustic wave (SAW) delay line. The SAW delay line generates a fixed delay time, which corresponds with a fixed radar distance. Thus, all systematic nonlinearities and stochastic phase errors of the FMCW system can be monitored and, afterwards, can be compensated for in real time. This linearization technique leads to a significant enhancement in dynamic range for a FMCW radar system. For this FMCW system, SAW delay lines with a linear phase characteristic have been designed using a linear optimization program. The delay line consists of two chirped and weighted interdigital transducers. For high volume, low-cost, and high-yield production of the required SAW structures, with linewidths down to 0.3 /spl mu/m, technological improvements had to be achieved, especially in photolithography. Based on these design and fabrication techniques, delay lines at 2.45 GHz operating at the fundamental and third harmonic with bandwidths up to 800 MHz have been realized.

Novel 77 GHz flip-chip sensor modules for automotive radar applications

Radar is the key technology for future automotive distance warning systems. Cost and production issues are still the major inhibitor to the development of this market. This paper reports on a new 77 GHz sensor module based on state-of-the-art MMICs and flip-chip technology. The implemented completely coplanar design is very attractive in terms of production simplicity.

A Small-Size High-Rejection LTCC Diplexer for WLAN Applications Based on a New Dual-Band Bandpass Filter.

This paper presents a new very small low temperature co-fired ceramic (LTCC) diplexer based on a dual-band bandpass filter for wireless LAN (IEEE 802.11 a/b/g) application. The diplexer and the dual-band filter design have been realized and demonstrated in this article. Measurement results agree quite well with simulation. The new type of such diplexer significantly reduces the number of components and the size of dual-band WLAN frontend modules.

LTCC triplexer for WiMax applications

In the present work, a design procedure for multiplexer development has been described. This procedure allows to reduce development time by using of some local optimizations instead of one global. LTCC (low-temperature co-fired ceramic) triplexer for WiMax (IEEE 802.16e) applications, designed in accordance with described procedure, has been presented. The measured results agree well with the simulation.

Vertical feedthroughs for millimeter-wave LTCC modules

This paper reports on novel types of vertical interconnects to be incorporated inside highly integrated LTCC Modules (Low Temperature Co-fired Ceramics). RF-transitions vertically interconnecting the top and bottom side of the LTCC are studied using alternatively CPW (coplanar waveguide) or microstrip feedlines. Vertical DC supply and control lines with integrated RF blocking capacitors are also demonstrated. LTCC test modules were fabricated and the performance of all feedthroughs successfully validated by scattering parameter measurements up to 40 GHz.

Novel high-rejection LTCC diplexers for dual-band WLAN applications

This paper presents novel highly-integrated LTCC diplexers for dual-band Wireless-LAN (IEEE 802.11 a/b/g) appli- cations. Two diplexer versions with integrated high-rejection filters have been realized and optimized for the receive and for the transmit mode. The measured results demonstrate excellent performance. The realized reference board demonstrates, that the number of components in a dual-band WLAN front-end design can be reduced by a factor of three, due to this new approach. Index Terms - Diplexers, Filters, Wireless LAN, LTCC.

Low profile LTCC balanced filter based on a lumped elements balun for WiMAX applications

This paper reports on a design of a balanced filter based on a new lumped LC type balun. The realization disadvantages of conventional LC baluns integrated in a front-end module have been discussed and a new low profile lumped-element balun has been proposed. The balanced filter is realized as a combination of a second order band pass filter and the novel LC balun with an additional low-pass circuit. The proposed layout has been realized using multilayer low temperature co-fired ceramic (LTCC) technology. The resulting structure exhibits excellent electrical performance, immunity to manufacturing tolerances and compactness. The realized low profile balanced filter is placed between two ground planes ensuring high electromagnetic compatibility which allows using this balanced filter as a building block of highly integrated WiMAX front-end modules.

Highly-integrated dual-band front-end module for WLAN and WiMAX applications based on LTCC technology

A very compact dual-band LTCC module supporting WiMAX IEEE 802.16e-2005 and Wi-Fi IEEE 802.11a/b/g standards is presented. The frontend module (FEM) integrates in less than 50mm2 all required passive and active functions for 1×2 (1 Transmit, 2 receive paths) MIMO operability. The FEM package has SMT compatible footprint and is 1.4mm high. Full FEM measurements results show good performance and fully validate the passive integration approach.

Implementation of a miniaturized lumped-distributed balun in balanced filtering for wireless applications

This paper reports on miniaturized lumped-distributed balun for balanced filtering applications. Detailed analysis of suppression performance of the lumped-distributed balun is introduced. Different types of baluns and their interconnection in series with filter were considered. Baluns have been implemented using LTCC technology and experimentally validated.