Norbert Henze

A Single-Stage PV Module Integrated Converter Based on a Low-Power Current-Source Inverter

This paper presents a transformerless three-phase inverter designed for the integration into a special type of a photovoltaic (PV) module, which is capable of providing an output voltage of several hundred volts. The chosen topology, a current-source inverter, features a single-stage power conversion system that directly feeds into the grid. The principle operation and control is described, and a modified modulation strategy is proposed to attenuate common-mode currents. A robust and highly efficient laboratory prototype of a 250-W module integrated converter has been implemented and tested. Its compact and flat design allows the direct attachment to the PV module.

GPS patch antenna with photovoltaic solar cells for vehicular applications

This paper describes the application of photovoltaic (PV) solar cells in planar antenna structures. The radiating patch element of a planar antenna is replaced by a solar cell. The original feature of a solar cell (DC current generation) remains, but additionally the cell is now able to receive and transmit electromagnetic waves. Both single solar cells as well as solar cell arrays can be used as antennas. However, the DC connection of the solar cells must be considered. By means of an elaborated series connection of the solar cells a harmful influence on the antenna properties may be avoided. Besides a general technical description, a solar-cell antenna for GPS applications is presented in detail. As a demonstrator, an aperture coupled patch antenna has been realised, which is suited for integration in vehicular glass roofs. The solar cell antenna is manufactured with commonly used production methods for solar modules. It turned out that some of the used materials degrade the antenna properties. Nevertheless, the comparison of measured and simulated antenna properties shows a good agreement, and the antenna works well with commercial GPS receivers. The DC voltage of the solar cells is about 18 V. Thus support of the car battery and the power supply is possible, which enables new applications like permanent cabin ventilation.

Investigation of planar antennas with photovoltaic solar cells for mobile communications

This paper describes the application of photovoltaic (PV) solar cells in planar antenna structures. The radiating patch element of a planar antenna is replaced by a solar cell. Furthermore radiating slots are built due to the cell spacing in a solar cell array. The original feature of a solar cell (DC current generation) remains, but additionally the solar cell is now able to receive and transmit electromagnetic waves. Both single solar cells as well as solar cell arrays can be used as antennas. At first some basics regarding the RF properties of solar cell patches are discussed. The efficiency of solar cell antennas is measured by means of the Wheeler Cap method, which is investigated by means of numerical simulations. The lossy substrate of the feed lines has the strongest influence on the antenna efficiency. Finally two applications are presented: a solar cell GPS antenna for vehicular applications and a solar cell slot antenna for mobile communications (GSM). The aim is to integrate these antennas into vehicular glass roofs which are covered with photovoltaic solar cells in order to deliver the electric power for the indoor ventilation of the car. The GPS antenna provides circular polarisation and a main lobe in zenith direction whereas the GSM antenna is vertically polarized and has a monopole-like radiation pattern. Both antennas are built up with commonly used solar cells. The comparison of measured and simulated antenna properties shows a good agreement.

Photovoltaic Power Supply and Antennas in one Device for Wireless Telecommunication Equipment

This paper describes the application of photovoltaic (PV) solar cells in planar antenna structures. The radiating patch element of a planar antenna is replaced by a solar cell. Furthermore radiating slots are built due to the cell spacing in a solar cell array. The original feature of a solar cell (DC current generation) remains, but additionally the solar cell is now able to receive and transmit electromagnetic waves. One single solar cell can be used as antenna, but it is also possible to integrate an antenna into a complete solar cell module which consists of a series connection of numerous cells. Several applications of this new device in the fields of satellite and mobile communications are outlined

Integrierte Planarantenne für Handfunktelefone und ihre Optimierung

Übersicht Es wird eine neue Antenne für Mobilfunkanwendungen im 1,8-GHz-Band (DCS 1800) vorgestellt, die sehr klein und in das Handygehäuse integrierbar ist. Diese Antenne wird als Dual Meandering Antenna (DMA) bezeichnet. Sie ist auf der Rückseite des Telefongehäuses angebracht. Die DMA stellt eine Weiterentwicklung der RCDLA (Radiation Coupled Dual-L Antenna) [1] dar. Die DMA ist eine platzsparende integrierbare Antenne, die durch einen zweifachen Knick des aktiven und passiven Strahlerelements entsteht. Die Eigenschaften der Antenne werden in dieser Arbeit diskutiert. Die Auswirkungen der Strahlergeometrie auf Impedanz und Bandbreite der Antenne werden ausführlich erläutert und daraus Hinweise zur Optimierung abgeleitet. Eine bezüglich der Bandbreite optimierte Antenne wird entwickelt und der Einfluß des Benutzers untersucht. Ebenso wird die Strahlungscharakteristik der Antenne mit und ohne Benutzer dargestellt, wobei die Abstrahlung in Richtung des Kopfes gegenüber einer Monopolantenne reduziert ist. Die numerische Analyse der Antenne erfolgt mit dem Programmpaket MAFIA.

Anwendung des FIT-Algorithmus zur numerischen Feldberechnung von Koaxialübergängen

The softwarepackage MAFIA is used for calculations of coaxial transitions. By means of simple discontinuities, the application of the Finite-lntegration-Technique is first checked. Reflection coefficients as well as field distributions inside the transitions are calculated. The simulation results show good agreement with theoretical found values. Practical configurations (male-female connector transition as well as cable-connector transition) are finally examined with regard to their reflection coefficient. The distribution of the electrical and magnetical field is represented.

Numerische Analyse aperturgekoppelter Streifenleitungsantennen mit MAFIA

Microstrip and planar antennas are widely used in the field of mobile communication and radar applications. For an accurate calculation of the antenna properties efficient numerical techniques are used. These are very valuable design tools. An aperture coupled microstrip antenna for applications in the X-Band (9.6 GHz) is simulated by means of MAFIA using the FIT-Algorithm (Finite Integration Technique). The results are compared with a simulation based on a combination of the integral equation method and the method of moments. The simulation results show very good agreement both with measurements of the reflection coefficient and the farfield of the antenna, and with results from the combined method of integral equation and method of moments.

Analytical analysis of antennas in the presence of a multilayered dielectric sphere with application to hand held terminals

The problem of a herzian dipole in the presence of a dielectric sphere is solved by expanding the electromagnetic field in the vector spherical harmonics and imposing the appropriate boundary conditions. The solution is generalized to a N-layered sphere. The algorithm is programmed as the RAME (Radiation Analysis by Multipole Expansion) code by means of Matlab. Specific choice of the location of the dipole gives short computation time. The output includes near-and far-field plots and efficiency. The results have been compared with static solutions when applicable and good agreement was found. The analysis is extended to the arc antenna which is otherwise only numerically solvable. The theory of RAME is presented, followed by results for testing the program. Finally RAME results relevant to personal communications are presented.