Optimum Antenna Design Research Articles

Design of High Gain Slotted Circular Microstrip Antenna for X-band Applications

In this study, new structures of circular microstrip antennas, which operating in X-band frequency using etched slots on the patch radiating, are designed and simulated. These slots are rectangular and crescent shapes in different sizes. The proposed structures are fed by a coaxial line feed. The antennas designed are simulated and studied in order to obtain the optimum performance of the proposed antenna using Ansoft High Frequency Structure Simulator. The simulated results were discussed in terms of reflection coefficient, input impedance, gain, radiation patterns and surface currents. It is found that the optimum antenna design has resonance frequency 9.346 GHz with a bandwidth of reflection coefficient of 705 MHz, which is required for X-band applications. Therefore, this optimum designed is helpful for many applications in the system of modern wireless communication.

Thermal Evaluation of a Micro-Coaxial Antenna Set to Treat Bone Tumors: Design, Parametric FEM Modeling and Evaluation in Multilayer Phantom and Ex Vivo Porcine Tissue

Bone cancer is rare in adults, the most affected persons by this disease are young people and children. The common treatments for bone cancer are surgery, chemotherapy, and targeted therapies; however, all of them have side-effects that decrease the patient’s quality of life. Thermotherapy is one of the most promising treatments for bone cancer; its main goal is to increase the tumor temperature to kill cancerous cells. Although some micro-coaxial antennas have been used to treat bone tumors, most of them are designed to treat soft tissue. Therefore, the purpose of this work is to analyze the thermal behavior of four micro-coaxial antennas specifically designed to generate thermal ablation in bone tissue to treat bone tumors, at 2.45 GHz. The proposed antennas were the metal-tip monopole (MTM), the choked metal-tip monopole (CMTM), the double slot (DS) and the choked double slot (CDS). The design and optimization of the antennas by using the Finite Element Method (FEM) allow to predict the optimal antenna dimensions and their performance when they are in contact with the affected biological tissues (bone, muscle, and fat). In the FEM model, a maximum power transmission was selected as the main parameter to choose the optimum antenna design, i.e., a Standing Wave Ratio (SWR) value around 1.2–1.5. The four optimized antennas were constructed and experimentally evaluated. The evaluation was carried out in multilayer phantoms (fat, muscle, cortical, and cancellous bone) and ex vivo porcine tissue at different insertion depths of the antennas. To fully evaluate the antennas performance, the standing wave ratio (SWR), power loss, temperature profiles, and thermal distributions were analyzed. In the experimentation, the four antennas were able to reach ablation temperatures (>60 °C) and the highest reached SWR was 1.7; the MTM (power loss around 16%) and the CDS (power loss around 6.4%) antennas presented the lowest SWR values depending on the antenna insertion depth, either in multilayer tissue phantom or in ex vivo tissue. These proposed antennas allow to obtain ablation temperatures with an input power of 5 W after 5 min of treatment; these values are lower than the ones reported in the literature.

Broadband THz Corrugated Bull’s Eye Antennas

A 3-dB gain and input impedance bandwidth enhancement technique for THz periodically corrugated metallic antennas, also known as Bull's Eye antennas, is presented. A novel design that exploits the depth qualities of the corrugations is introduced, by employing two different depth values for two sets of indented rings. While the gain bandwidth of most single-depth planar corrugated antennas is limited, the 3-dB gain bandwidth of the proposed dual-depth design is expanded along with a high maximum gain. The simulated optimum model of 10 rings at around 300 GHz exhibits a 3-dB gain bandwidth of 8.85% with a maximum gain at broadside of 21.3 dBi. A leaky-wave analysis has been performed via a simple transcendental equation at the level of the gap openings in order to explain the antenna principle of operation. A prototype of the optimum antenna design has been fabricated and measured. The typical subwavelength slot feeding of Bull's eye corrugated antennas is substituted with an easy-to-fabricate open waveguide aperture, yielding a broadband matching performance. Measured results demonstrate a good agreement with simulations and validate the proposed antenna design.

Design and Simulation of Microstrip Antenna Using Composite Right/Left Handed Transmission Line (CRLH-TL) Technique for LTE and Radar Applications

A compact metamaterial inspired antenna operates at LTE and Radar applications is introduced in this paper. Control and manipulation of electromagnetic waves is at the heart of many industries from wireless communication, internet and optical data storage to imaging and displays. Progress in these technologies places challenging demands on material properties and therefore structured electromagnetic materials. Metamaterials are a special class of structured materials. Patterning on the sub-wavelength scale allows precise engineering of their electromagnetic properties over a range going far beyond natural media. In this paper, microstrip antenna consists of radiating patch and two parasitic elements (open-loop ring resonators) to serve coupling bridges with partial ground plane and composite right / left-handed transmission line (CRLH-TL) embedded in the patch antenna. The antenna topology possesses an area 26×37×1.27 mm3.The analysis and design is simulated and optimized commercial software. The good agreement between the theoretical expectation and the simulation results is observed. Finally, the proposed optimum antenna design structure has been fabricated and the measured S-parameters, VSWR of the proposed structure can be analyzed with network analyzer to demonstrate the excellent performance and meet the requirements for LTE and Radar applications.

Study on bandwidth enhancement techniques of microstrip antenna

In this paper we present a Novel Triangular UWB microstrip antenna which offers an ultra-wide bandwidth (UWB) greater than 8GHz. This optimum antenna design provides satisfactory gain all over the UWB. The study includes partially truncating the ground plane (defected ground), inserting slits in the triangular radiating patch, and using different substrate materials in order to obtain band-notched UWB. The simulation experiments have been carried out using the IE3D Zeland software. The final antenna design is fabricated on two substrates; FR4 and Droid 5880 (Teflon). The practical measurements well agree with the simulation results.

Monopole Patch Antenna with Dual Band of 2.4 and 5 GHz Designed for Wireless LAN Applications

A compact prototype of dual band monopole antenna has been fabricated on PCB with small overall size of 36.6 mm×47 mm. By the trial of simulation to tune the dimensions of PCB, an optimum design of antenna can be obtained. Dual resonances excited in 2.4 and 5 GHz bands. For return loss more than 9.6 dB, the achieved bandwidths are 2.41 to 2.77 GHz in 2.4 GHz band and 5.11 to 5.83 GHz in 5 GHz band. The return loss ( ) can keep larger than 9.6dB within the bands of 2.4 and 5 GHz.

Characterization of a Tranceiving Antenna Concept for Microwave Heating and Thermometry of Superficial Tumors - Abstract

A tranceiving printed circuit antenna concept, intended to be used for simultaneous heating and thermometry in hyperthermia therapy, is introduced and experimentally investigated in a liquid phantom. Two important questions have been addressed. First, optimum antenna design related to the depth-of-sensitivity and lateral beam width for microwave radiometry detection of subcutaneous objects. Second, optimum antenna design aimed at producing large area hyperthermia at superficial depth. Due to the nature of the problem, it is not possible to optimize one antenna configuration design to meet both these criteria. Instead an integrated dual antenna concept, consisting of one transmitting and one receiving antenna, is proposed. By means of a scanning electric field probe the radiated electric field distribution (E2) was measured for the concept in a homogeneous lossy medium. The measurements were further parameterized in terms of four performance indices defined in this work. A microstrip spiral antenna is shown to be appropriate for thermometry in the frequency range from 1400 MHz to 2400 MHz. For microwave heating we propose a microstrip coplanar grounded ring antenna. Analysis reveals that this antenna has the ability to produce effective radiation out to the periphery of the aperture. Due to the integration of both antennas onto thin and flexible printed circuit board substrate, the tranceiving device is both lightweight and conformable. From the analyses we conclude that the concept has the potential of being an effective building block of larger array systems, for noninvasive thermometry and cancer treatment of large superficial tissue regions.