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.

Compensation of Dispersion in Sinuous Antennas for Polarimetric Ground Penetrating Radar Applications

In order to improve the accuracy of subsurface target classification with ground penetrating radar (GPR) systems, it is desired to transmit and receive ultra-wide band pulses with varying combinations of polarization (a technique referred to as polarimetry). The sinuous antenna exhibits such desirable properties as ultra-wide bandwidth, polarization diversity, and low-profile form factor, making it an excellent candidate for the radiating element of such systems. However, sinuous antennas are dispersive since the active region moves with frequency along the structure, resulting in the distortion of radiated pulses. This distortion may be compensated in signal processing with accurately simulated or measured antenna phase information. However, in a practical GPR, the antenna performance may deviate from that simulated, accurate measurements may be impractical, and/or the dielectric loading of the environment may cause deviations. In such cases, it may be desirable to employ a simple dispersion model based on antenna design parameters which may be optimized in situ. This paper explores the dispersive properties of the sinuous antenna and presents a simple, adjustable, model that may be used to correct dispersed pulses. The dispersion model is successfully applied to both simulated and measured scenarios, thereby enabling the use of sinuous antennas in polarimetric GPR applications.

Design of an Ultra-Wideband Four Arms Sinuous Antenna

Due to the advantages of ultra-wideband, single caliber, symmetric pattern, full polarization, the sinuous antennas have gradually displaced the traditional spiral antennas in the Missile guider, reflector feed, wideband direction finding system. Based on the traditional planar sinuous antennas, this paper designed a novel 2-22 GHz 3D sinuous antenna in the conical form. Results show that the designed antenna showed high performance within 2-22 GHZ frequency band.

High Gain Compact Strip and Slot UWB Sinuous Antennas

Three ground-backed compact strip-and slot-sinuous antennas are analyzed. Proposed configuration allows for a single lobe, polarization-versatile, high efficiency, and ultrawide band antenna not needing a cumbersome lossy back cavity typical of conventional single-lobe sinuous antennas. Simulations show attained performances as well as tuning possibilities.