The commercial and military telecommunication systems require ultrawideband antennas. The small physical size and multi-band capability are very important in the design of ultrawideband antennas. Fractals have unique properties such as self-similarity and space-filling. The use of fractal geometry in antenna design provides a good method for achieving the desired miniaturization and multi-band properties. In this communication, a multi-band and broad-band microstrip antenna based on a new fractal geometry is presented. The proposed design is an octagonal fractal microstrip patch antenna. The simulation and optimization are performed using CST Microwave Studio simulator. The results show that the proposed microstrip antenna can be used for 10 GHz -50 GHz frequency range, i.e., it is a super wideband microstrip antenna with 40 GHz bandwidth. Radiation patterns and gains are also studied.

A New Super Wideband Fractal Microstrip Antenna

In this paper we propose a circularly polarized (CP) microstrip antenna on a suspended substrate with a coplanar capacitive feed and a slot within the rectangular patch. The antenna has an axial ratio bandwidth (< 3 dB) of 7.1%. The proposed antenna exhibits a much higher impedance bandwidth of about 49% (S11 < -10 dB) and also yields return loss better than -15 dB in the useful range of circular polarization. Measured characteristics of the antenna are in good agreement with the simulated results. The radiation patterns indicate good cross polarization rejection and low back lobe radiations. The design proposed here can be scaled to any frequency of interest.

/pdf/broadband-suspended-microstrip-antenna-for-circular-2gyb6ay7yq.pdf

Broadband Suspended Microstrip Antenna For Circular Polarization

A novel fractal antenna-array type is proposed. The design is based on the Sierpinski rectangular carpet concept. However, the generator is a circular ring area, fllled with radiating elements, so the higher stages of the fractal development produce large arrays of circular rings which, besides the high directivity, have the advantage of the almost uniform azimuthal radiation pattern, attribute that many applications require. The introduced arrays can operate as direct radiating multi-beam phased arrays and meet the requirements of satellite communications links: high End of Coverage (EOC) directivity, low Side Lobe Level (SLL) and high Career to Interference ratio (C=I). These operational indices were further optimized by a synthesized multi-objective and multi-dimensional Genetic Algorithm (GA) which, additionally, gave arrays no more than 120 elements.

/pdf/novel-fractal-antenna-arrays-for-satellite-networks-circular-14bum69urg.pdf

Novel fractal antenna arrays for satellite networks: circular ring sierpinski carpet arrays optimized by genetic algorithms

The small physical size and multiband capability are significant in the design of ultrawideband (UWB) antennas. Fractal geometry provides a good method for achieving the desired miniaturization and multiband performances. Furthermore, using a dielectric resonator improves bandwidth and radiation characteristics. A combination of these methods in the UWB antenna design is presented. The proposed design is a new hybrid dielectric resonator antenna (DRA) excited by a new fractal monopole antenna. The simulation and optimization have been carried out using Ansoft HFSS. The simulation and measurement results show that the proposed structure provides a huge bandwidth ranging from 2 to 40 GHz. Radiation patterns and gains show a good agreement over the bandwidth.

/pdf/a-new-super-wideband-fractal-monopole-dielectric-resonator-3wk88taqb1.pdf

A New Super Wideband Fractal Monopole-Dielectric Resonator Antenna

The design and characterization of a compact ultrawideband (UWB) antenna is presented in this letter. The bases for achieving such an UWB operation are through using semicircular microstrip monopole antenna and introducing a metamaterial as an artificial magnetic conductor (AMC). The AMC reduced antenna size, enhanced antenna gain and bandwidth, and decreased the cross-polarization effect. A spiral artificial magnetic conductor (SAMC) is used as a ground plane with one and four arms to further improve the antenna performance. Furthermore, to reduce surface wave propagation and decrease bandwidth discontinuity, holes surrounding the antenna structure are drilled in the substrate. The new antenna provides an impedance bandwidth of more than 35 GHz with S11 < -10 ± 0.5 dB. The SAMC antenna has a wide frequency range for practical applications ranging from all required wireless communication bands, i.e., GSM 900 MHz, ISM band, Bluetooth, wireless LAN and S-band, to new medical applications. Details of the proposed antenna design are described, and experimental results are presented.

Ultrawide Bandwidth Umbrella-Shaped Microstrip Monopole Antenna Using Spiral Artificial Magnetic Conductor (SAMC)

https://www.jpier.org/pierc/pierc02/02.08031005.pdf

Ultra wideband fractal microstrip antenna design

Fractals have singularity properties. Therefore in recent years, antenna designers use fractal antennas in multi-frequency antenna designing.

In this paper, via fractal geometry in wired loop square antenna and selecting suitable place for feeding, we've achieved to an ultra wideband antenna. Modelling and simulation is performed via SUPERNEC simulator software. Results of simulations show that suggested antenna is ultra wideband.

Javad Rowhani

Papers

Ultra wideband fractal microstrip antenna design

Ultra wideband fractal antenna design