Alexander Stark

A Broadband Vertical Transition for Millimeter-Wave Applications

This paper reports on a broadband vertical transition, which shows superior characteristics from DC up to 85 GHz. The design and analysis of the novel transition are presented. The proposed transition is practicable in low cost substrates and requires only three vias, which ensures compact and easy realization. Further, the usefulness of this transition as a 2nd -level interconnection for multilayer modules with excellent robustness against lateral misalignment is presented. The measurement results of back-to-back arrangements exhibit good performances up to 60 GHz and show reasonable agreement with simulation.

A Packaged Ultrawideband Filter with High Stopband Rejection [Application Notes]

In recent years, the promises of ultrawideband (UWB) technology have sparked the interest of the research community, and since 2002, when the Federal Communications Commission (FCC) approved the commercial use of the frequency band between 3.1 GHz and 10.6 GHz for UWB systems, research in this field has gained momentum. The first years after the FCCs release have seen an almost exponential increase in publications on this topic, as is shown in Figure 1.

Broadband EBG Structures with Compact Unit Cell

The design of a hook-like EBG structure with a small unit cell size is presented in this paper. This hook-like structure has a high inductance of the equivalent electrical LC-circuit, which enables the realization of broadband band-gaps at very low center frequencies. Simulation and measurements show, that the novel structure improves the relative bandwidth by 77% and lattice size by 59% compared to the standard mushroom-like EBG structure. In addition, a second EBG structure with a relative bandwidth of 15% is presented, which is generated with the aid of a genetic algorithm (GA). Measurement results of the proposed designs show good agreement with simulation.

In-situ probes for patch antenna array calibration

A novel calibration network for patch antennas is proposed. We introduce magnetically coupled in-situ probes, which excite the fundamental patch mode. In that way, finite array effects and mutual coupling are taken into account, providing the opportunity for accurate online calibration of active antenna terminals. The specific advantages of the approach are demonstrated for linearly polarized patch antennas. Realization aspects of the multilayer antenna are discussed and the effect of some fabrication imperfections are investigated. Measured S-parameters as well as radiation simulation results of a single patch with the integrated probes are presented. Based on simulation of antenna arrays with in-situ probes the calibration accuracy is given in theory.

Broadband Patch Antenna with Polarization Multiplexing for K-Band Array Applications

Abstract A multilayer K-band patch antenna element featuring polarization multiplexing is presented. It relies on a previously published design providing high polarization purity. The layer stack and, in essence, the geometry are preserved. Left- and right-handed circular polarization (LHCP/RHCP) are realized without hybrid coupler, the two feeds still sharing the same layer. The arrangement is thus very compact. For interpretation, the simulation results are cast into an equivalent circuit model. Measurements performed on a multilayer antenna with vertical transitions confirm the concept.