Jerzy Kowalewski

Shape Memory Alloy (SMA)-Based Pattern-Reconfigurable Antenna

This letter presents a realization method of reconfigurable antenna systems based on smart materials. The reconfigurability is obtained by utilizing shape memory alloy directors. This realization method offers a longer lifetime and lower energy consumption than conventional approaches such as microelectromechanical systems (MEMS) or p-i-n diodes. As a proof-of-concept, a compact reconfigurable antenna for the 2.6-GHz Long Term Evolution (LTE) band was designed. The designed antenna is a quasi-Yagi antenna with its directors made from shape memory alloy. This antenna is made to be installed in a standard car-roof antenna housing. A prototype of the antenna presented here has been fabricated and measured.

Compact, Teflon embedded, dual-polarized ultra wideband (UWB) antenna

In this paper a compact dual-polarized Ultra Wideband antenna applicable to an indoor radar is presented. Apart from a broad bandwidth, which is between 3.5 to 13.5 GHz, the main features are high polarization purity and small dimensions. The compact size is determined by the embedding in a dielectric (Teflon). The antenna itself is tapered slot lines based, typically known as Vivaldi antennas. Additionally to the description of the design also measurement results of a prototype are presented.

Pattern reconfigurable antenna with four directions hidden in the vehicle roof

Chassis integrated antenna cavities offer ten times the space of conventional automotive roof mounted antenna modules and can be fully concealed beneath the roofline. A pattern reconfigurable antenna for 2.6 GHz LTE is measured inside an automotive chassis cavity. The antenna can be electrically reconfigured to radiate towards the front, back, left or right side of the vehicle. Measurement results show that the antenna retains this ability when being hidden beneath the roof, proving that it is possible and feasible to hide antennas utilizing pattern diversity inside chassis cavities.

A compact pattern reconfigurable antenna utilizing multiple monopoles

A reconfigurable antenna for optimal radiation patterns used for automotive urban scenarios is proposed in this paper. The antenna is anticipated to radiate in the best sub-channels obtained from a channel simulation. The antenna consist of two serially fed monopoles placed on one substrate. The pattern switching is realized by changing the phase of the feeding signal. Thus, two directional patterns are realized, whereby the first is in and opposite the driving direction and the second is shifted by 90° in azimuth, thus orthogonal to the driving direction. The chosen frequency of operation is 2.45 GHz. As a proof of concept two prototypes of the antenna, one utilizing p-i-n diodes and one using MEMS (micro-electro-machanical switch) as switching elements have been fabricated and measured. The maximum gain achieved is about 5 dBi. The measurement results show that only slight improvement is achieved if MEMS are used instead of p-i-n diodes.

Realization of a pattern reconfigurable antenna employing PIN diodes

A compact pattern reconfigurable antenna for mobile communication is presented in this work. The presented antenna shows a good matching between 1.5 GHz and 2.5 GHz. It can therefore be applied for the 1.8 GHz mobile communication band and for the 2.4 GHz WiFi (wireless fidelity) band. Furthermore the antenna is capable of switching between three different directivity patterns. An omnidirectional pattern is realized in one of the states. The two other states generate a directional beam. The beams are shifted by 180° in azimuth and directed towards opposite sides of the antenna. The antenna elements can be switched between activated with the use of PIN diodes. With the chosen construction the PIN diodes can be easily fed with the help of a coaxial bias-T and a simple feeding structure. The measurement results prove a good performance of the antenna.

A simulator for multi-user automotive radar scenarios

Radar is an essential element of state of the art advanced driver assistance systems. In the foreseeable future, radar will be an indispensable sensor for the use in affordable, automated driven cars. Simulation tools are the key for an efficient development process and hence will lower the price of sophisticated driver assistance systems. Therefore, the development of adequate simulators is important for suppliers, car makers, and final consumers. This paper introduces the concept of such a simulator for multi-user automotive radar scenarios and presents selected simulation results for a use case of radar interference.

A pattern reconfigurable automotive LTE antenna employing synthesized radiation patterns

This work presents a pattern reconfigurable automotive antenna optimized for the 2.6GHz band reserved in Europe for the use of the Long Term Evolution (LTE) communication standard. Pattern reconfiguration is the ability of an antenna to switch between at least two fixed radiation patterns (states). In this work a special feeding network utilizing PIN diodes is used to switch between the two states. One possible trigger for the switching from one to another reconfiguration state is a bad SNR, a condition to achieve a diversity gain. A special antenna synthesis method was used to determine the antenna radiation patterns to be used for pattern reconfiguration. Finally the antenna is simulated, fabricated and measured.

Compact pattern reconfigurable LTE antenna

This paper presents a compact pattern reconfigurable antenna for automotive mobile systems. The presented antenna operates in the 2.6 GHz LTE band in Europe and is capable of switching between four different directivity patterns. The generated main beams for these four states are shifted by 90° in azimuth in respect to one another. The antenna elements can be switched between active state or reflector state with the use of PIN diodes. With the chosen construction the PIN diodes can be easily fed with the help of a coaxial bias-T and a simple feeding structure. The measurement results prove good performance and the suitability for use in LTE applications.

Realization of a synthesized compact automotive roof-top LTE antenna

In this work a compact automotive antenna optimized for the 800MHz band of the Long Term Evolution (LTE) communication standard is proposed. The inverted F antennas (IFAs) radiation pattern is determined by a special antenna synthesis method. To overcome the narrowing of the bandwidth resulting from miniaturization of the antenna a parasitic element near the fed element is used. Finally the antenna is simulated, realized and measured.

A trident like antenna with reconfigurable patterns for automotive applications

Within the scope of this work, a reconfigurable antenna for automotive applications has been developed and constructed. The concept of planar parasitic array has been chosen due to its size. Furthermore, as an improvement to this concept, the parasitic elements were also used as active radiators. The antenna realizes four reconfigurable patterns that cover the angular regions in and against the driving direction as well as those orthogonal to the driving direction. Additionally a DC feeding network using metamaterials to decrease its influence on antenna characteristics is proposed. The measurement results match the simulated results and maximal gain of about 8.5 dBi is obtained.