Research of a Fractal Microstrip Antenna Based on the Modified Minkowski Curve of the Second Iteration

Evolving telecommunications systems require modern antennas with improved performance. The creation of miniature antennas with a high gain, multi-band properties and defined polarization is an urgent task. New challenges in the reception and emission of electromagnetic waves are being solved in different ways. The use of fractals in the construction of antennas is becoming widespread. This article presents the results of a study of fractal microstrip antenna of the second iteration based on the Minkowski geometry. The main parameters such as the reflection coefficient, directivity and efficiency are described. Resonance frequencies and directional patterns at these frequencies as well as bandwidths are shown. Conclusions concerning the possibility of using this type of antenna in various applications are drawn.

Application of Genetic Algorithm for Binary Optimization of Microstrip Antennas: A Review

<abstract> <p>Researchers have proposed applying optimization techniques to improve performance of microstrip antennas (MSAs) in terms of bandwidth, radiation characteristics, polarization, directivity and size. The drawbacks of the conventional MSAs can be overcome by optimizing the antenna parameters while keeping a compact configuration. Applying a global optimizer is a better technique than using a local optimizer or a trial and error method for performance enhancement. This paper discusses genetic algorithm (GA) optimization of microstrip antennas presented by the antenna research community. The GA optimization procedure, antenna parameters optimized by using GA and the optimization objectives are presented by reviewing the literature. Further, evolution of GA in the field of MSAs and its significance are explored. Application of GA optimization to design broadband, multiband, high-directivity and miniature antennas is demonstrated with the support of several case studies giving an insight for further developments in the field.</p> </abstract>

A wearable UHF RFID tag antenna-based metamaterial for biomedical applications

The development of miniature antennas for bio-medical applications has attracted the attention of many researchers in the last years. In this letter, we provide a miniature antenna for the RFID tag for identifying patients in African and European hospitals. The proposed antenna is designed on a flexible silicon substrate with a relative dielectric constant of 11.9 and a thickness of 1.6mm. An in-depth study of the proposed wearable antenna was made in free space and on human tissue. The achieved results showed good performance in terms of miniaturization, bandwidth, impedance matching and, reading distance. The presented tag antenna is designed and simulated by using CST-MWS solver and the results were validated by HFSS and both results are in good agreement.

Miniaturization of Printed Microstrip Antennas Array by Using Defected Ground Structure Technique

In this chapter, the authors present different techniques used to miniature microstrip antennas, particularly planar antennas array, for different applications demanding small dimensions. This will cover DGS, slot technique, and metamaterials. After the presentation of these techniques based on theoretical studies, the second part of this chapter will be about the authors' contribution in the miniaturization of microstrip antennas arrays. This part will include the presentation of some miniature antennas array which they have validated into simulation and measurement by using DGS techniques. The different structures were validated into simulation by using tow electromagnetic solvers ADS (advanced design system) and CST-MW (computer simulation technology) which permit one to validate and to verify the different performances of antennas arrays as radiation pattern, matching input impedance and small dimensions.

Numerical simulation of miniature antennas applicators of microwave radiometry for diagnostics of the functional state of the brain

This paper describes the use of Finite Difference Time Domain technique of numerical modeling for development and simulation symmetrical dipole with triangular shoulders placed in a cylindrical housing and a spiral antenna placed in a cylindrical housing for use in microwave radiometry. The new sensors have been tested and validated on different phantoms and biological tissues. Results suggest sufficient characteristics of broadband antennas for potential use in brain functional diagnostics.

Efficiency of the Miniature Anti-jam GNSS Antenna Array

The use of the miniature controlled reception pattern antennas (CRPAs) in GNSS equipment is one of the trends in GPS, Baidow, GLONASS development. A miniaturized GPS antenna array technology reduces the size of the antenna elements and the array dimensions. Miniature CRPAs are in demand not only with mass consumer of GPS/GLONASS house-hold equipment, but with expert users of complex hardware as well, where high-tech multi-sensor miniature antenna systems (AC) can be applied. Such types of AC used for intelligent control of spatial selectivity are considered as antenna arrays. The advantages of miniature CRPAs with anti-jamming capability include possibility to be installed on vehicles where it used to be impossible due to their size. The negative effect of miniaturization is in degradation of some antennas characteristics, such as gain, suppression of the reverse lobe of radiation pattern (RP), a heterogeneity of RP. In miniature antennas, the resonator interinfluence increases, that leads to distortion of individual emitters RP and to the in-crease of the total RP lobe of the antenna array irregularity, as well as the width of RP lobe. Designers take special measures to reduce the interinfluence of the resonators. However, they are not fully described in the available literature. Therefore, the achieved performance of miniature CRPAs is in great interest. The final criterion (from a consumer point of view) is in effective functional of a device containing a miniature CRPA, the degradation of its parameters in compare with traditional CRPA equipment of expert users. The authors focus on property investigation of miniature CRPAs manufactured primarily by US industry. Specifications of two antennas and some expected details of the miniaturized antenna array technology are described along with the test results of their ability to perform the objective function jammer suppression. The article contains the results obtained from independent testing of electrodynamics parameters of miniature L1/L2 frequency CRPA and its design analysis. The experimental data of sensor interinfluence are outlined. The measures to reduce the sensor interinfluence are take into account. The efficiency of the miniature antenna is estimated in the process of interference suppression by means of computer simulation. The Monte-Carlo method is applied. For the sake of generality, two types of algorithm for interference suppression are used.