Sinuous Antenna for UWB Radar Applications

In this paper, the recent progress on sinuous antennas is detailed, focusing the attention on the antenna geometry, dielectric structure, and miniaturization techniques. In the first part, we introduce the basic principles of the frequency-independent antenna, in particular the self-complementary and log-periodic geometries, as well as the antenna geometries, all characterized in terms of angles. The operating principles, main advantages, system design considerations, limits, and challenges of conventional sinuous antennas are illustrated. Second, we describe some technical solutions aimed to ensure the optimal trade-off between antenna size and radiation behavior. To this aim, some special modification of the antenna geometry based on the meandering as well as on the loading with dielectric structures are presented. Moreover, the cavity backing technique is explained in detail as a method to achieve unidirectional radiation. Third, we present a new class of supershaped sinuous antenna based on a suitable merge of the 2D superformula and the sinuous curve. The effect of the free parameters change on the antenna arm geometry as well as the performance improvement in terms of directivity, beam stability, beam angle, gain, and radiating efficiency are highlighted.

Structure-Integrated Loudspeaker Using Fiber-Reinforced Plastics and Piezoelectric Transducers—Design, Manufacturing and Validation

In the present study, it could be shown that by integration of a piezoceramic transducer in a fiber-reinforced door side panel, a flat loudspeaker can be realized. Taking into account the given restrictions, the integration position has been identified, where the geometry decouples the vibrating membrane from the supporting surface. With the help of an acoustic finite-element simulation, the main design variables of the integration position were found and the relevant effects for sound radiation were made visible. The manufacturing of the test specimen with piezoceramic transducers was performed using vacuum-assisted resin infusion and the long fiber injection procedure. The effect on the real sound radiation behavior of the door side panel with a material-immanent loudspeaker was experimentally determined using laser scanning vibrometry and sound pressure measurements. The presented work shows, for the first time, the high potential of acoustic functionalization of lightweight structures during the manufacturing process for the realization of lightweight and space-saving loudspeakers in a production-ready process.

A Novel Compact Microstrip UWB Rectangular Stair Slot Antenna for the Analysis of Return Losses

This article deals with the various designs of a novel compact microstrip fed UWB antenna to investigate the corresponding return losses of different structures. The dimension of the designed antenna is 33 x 19 x 1.9 mm3 with FR4 substrate and it can be operated from 2.846 - 11.7458 GHz. The effects of varying the structure of antenna are to exhibit the investigation of corresponding return losses. Different structures of antenna are simulated in Ansoft HFSS simulator. The results of return losses and radiation patterns are explored with the ultra wide band (UWB) rectangular Stair slot antenna. The modified structure of antenna shows the minimized return loss with an enhanced bandwidth that satisfies good UWB characteristics. Antenna performance can also be explored from the radiation behavior of the antenna which is relatively omni-directional pattern for rectangular Stair slot antenna