DFM(A)- aspects for a horn antenna design

In this paper aspects of design for manufacturability and assembly (DFMA) are applied to the design of coaxially fed standard gain horn antenna for 1.70 - 2.60 GHz. Possibilities to utilize cross-technological approach method is examined. Methods of DFMA for laser processing are covered and practical design guides and methods are developed. Antenna construction for easy manufacturing and specialized performance is shown. Required dimensions and tolerances are discussed and suitable materials for laser processing are selected.

Antenna Design for Contactless IC Card Applications

Contactless integrated circuit cards are one form of application of radio frequency identification. They are used in applications such as access control, identification, and payment in public transport. The contactless IC cards are passive which means that both the data and the energy are transferred to the card without contact using inductive coupling. Antenna design and optimization of the design for contactless IC cards defined by ISO/IEC14443 is studied. The basic operation principles of contactless system are presented and the structure of contactless IC card is illustrated. The structure was divided between the contactless chip and the antenna. The operation of the antenna was covered in depth and the parameters affecting to the performance of the antenna were presented. Also the different antenna technologies and connection technologies were provided. The antenna design process with the parameters and the design tools isillustrated and optimization of the design is studied. To make the design process more ideal a target of development was discovered, which was the implementation of test application. The optimization of the antenna design was presented based on the optimization criteria defined in this study. The solution for the implementation of these criteria and the effect of each criterion was found. For enhancing the performance of the antenna a focus for future study was proposed.

A hands-on education project: antenna design for inter-CubeSat communications

CubeSat platforms have become a de facto standard for universities willing to initiate space-technology activities with students. These small satellite platforms ease the implementation of hands-on education projects and opening the apertures of new research areas. Moreover, due to the limited volume (a 10 cm cube) and power (1 W), the application of imaginative solutions is mandatory. This leads to new innovation processes in the course of CubeSat projects. In this paper, we present a hands-on education project the aim of which is the specification, design, building and measurement of an antenna for communication between nanosatellites and, in particular, CubeSats. The project lies within the framework of ETSIT-UPM innovative education activities in the area of space technology, where students play a leading role in real engineering projects.

Design and optimization of na ultra wideband and compact microwave antenna for radiometric monitoring of brain temperature

We present the modeling efforts on antenna design and frequency selection to monitor brain temperature during prolonged surgery using noninvasive microwave radiometry. A tapered log-spiral antenna design is chosen for its wideband characteristics that allow higher power collection from deep brain. Parametric analysis with the software HFSS is used to optimize antenna performance for deep brain temperature sensing. Radiometric antenna efficiency (eta) is evaluated in terms of the ratio of power collected from brain to total power received by the antenna. Anatomical information extracted from several adult computed tomography scans is used to establish design parameters for constructing an accurate layered 3-D tissue phantom. This head phantom includes separate brain and scalp regions, with tissue equivalent liquids circulating at independent temperatures on either side of an intact skull. The optimized frequency band is 1.1-1.6 GHz producing an average antenna efficiency of 50.3% from a two turn log-spiral antenna. The entire sensor package is contained in a lightweight and low-profile 2.8 cm diameter by 1.5 cm high assembly that can be held in place over the skin with an electromagnetic interference shielding adhesive patch. The calculated radiometric equivalent brain temperature tracks within 0.4 degrees C of the measured brain phantom temperature when the brain phantom is lowered 10. C and then returned to the original temperature (37 degrees C) over a 4.6-h experiment. The numerical and experimental results demonstrate that the optimized 2.5-cm log-spiral antenna is well suited for the noninvasive radiometric sensing of deep brain temperature.

Design and Development of re configurable compact cross patch antenna for switchable polarization

Antennas are necessary and vital components of communication and radar systems, but sometimes their inability to adjust to new operating scenarios can limit system performance. Reconfigurable antennas can adjust with changing system requirements or environmental conditions and provide additional levels of functionality that may result in wider instantaneous frequency bandwidths, more extensive scan volumes, and radiation patterns with more desirable side lobe distributions. Their agility and diversity created new horizons for different types of applications especially in cognitive radio, Multiple Input Multiple Output Systems, satellites and many other applications. Reconfigurable antennas satisfy the requirements for increased functionality, such as direction finding, beam steering, radar, control and command, within a confined volume. The intelligence associated with the reconfigurable antennas revolved around switching mechanisms utilized. In the present work, we have investigated frequency reconfigurable polarization diversity antennas using two methods: 1. By using low-loss, high-isolation switches such as PIN diode, the antenna can be structurally reconfigured to maintain the elements near their resonant dimensions for different frequency bands and/or polarization. 2. Secondly, the incorporation of variable capacitors or varactors, to overcome many problems faced in using switches and their biasing. The performances of these designs have been studied using standard simulation tools used in industry/academia and they have been experimentally verified. Antenna design guidelines are also deduced by accounting the resonances. One of the major contributions of the thesis lies in the analysis of the designed antennas using FDTD based numerical computation to validate their performance.

Design and demonstration of an electronically scanned reflectarray antenna at 100 GHz using multiresonant cells based on liquid crystals

The design, fabrication and measured results are presented for a reconfigurable reflectarray antenna based on liquid crystals (LC) which operates above 100 GHz. The antenna has been designed to provide beam scanning capabilities over a wide angular range, a large bandwidth and reduced Side-Lobe Level. Measured radiation patterns are in good agreement with simulations, and show that the antenna generates an electronically steerable beam in one plane over an angular range of 55º in the frequency band from 96 to 104 GHz. The Side Lobes Level is lower than -13 dB for all the scan angles and -18 dB is obtained over 16% of the scan range. The measured performance is significantly better than previously published results for this class of electronically tunable antenna, and moreover verifies the accuracy of the proposed procedure for LC modeling and antenna design.

Design of a compact ultra-wideband antenna

A simple method for the design of ultra-wideband antennas in planar format is presented. This method is demonstrated for a high-dielectric-constant substrate material, which allows for a considerable antenna size reduction. Simulations are performed using Ansoft's High-Frequency Structure Simulator (HFSS) for antennas assuming Du-Pont951 (epsilon(r) = 7.8) and RT6010LM (epsilon(r) = 10.2) substrates. For the 1-mm-thick DuPont951, the designed antenna with 22 X 28 nun dimensions features a 10-dB return-loss band width front 2.7 GHz to more than 15 GHz. For the 0.64-mm-thick RT6010LM a 20 X 26 nun antenna exhibits a 10-dB return loss bandwidth from 3.1 to 15 GHz. Both antennas feature nearly omnidirectional properties across the whole 10-dB return-loss bandwidth. The validity of the presented UWB antenna design strategy is confirmed by measurements performed on a prototype developed on RT6010LM substrate. (c) 2006 Wiley Periodicals, Inc.

Customization of the design of antenna using genetic algorithm and finite-difference time-domain technique

Antenna design is an iterative process in which structures are analyzed and changed to comply with certain performance parameters required. The classic approach starts with analyzing a "known" structure, obtaining the value of its performance parameter and changing this structure until the "target" value is achieved. This process relies on having an initial structure, which follows some known or "intuitive" patterns already familiar to the designer. The purpose of this research was to develop a method of designing UWB antennas. What is new in this proposal is that the design process is reversed: the designer will start with the target performance parameter and obtain a structure as the result of the design process. This method provided a new way to replicate and optimize existing performance parameters. The base of the method was the use of a Genetic Algorithm (GA) adapted to the format of the chromosome that will be evaluated by the Electromagnetic (EM) solver. For the electromagnetic study we used XFDTD™ program, based in the Finite-Difference Time-Domain technique. The programming portion of the method was created under the MatLab environment, which serves as the interface for converting chromosomes, file formats and transferring of data between the XFDTD™ and GA. A high level of customization had to be written into the code to work with the specific files generated by the XFDTD™ program. Two types of cost functions were evaluated; the first one seeking broadband performance within the UWB band, and the second one searching for curve replication of a reference geometry. The performance of the method was evaluated considering the speed provided by the computer resources used. Balance between accuracy, data file size and speed of execution was achieved by defining parameters in the GA code as well as changing the internal parameters of the XFDTD™ projects. The results showed that the GA produced geometries that were analyzed by the XFDTD™ program and changed following the search criteria until reaching the target value of the cost function. Results also showed how the parameters can change the search criteria and influence the running of the code to provide a variety of geometries.

Design Aspects of a Broadband Beam-Reconfigurable Leaky-Wave Antenna

Design aspects of a novel beam-reconfigurable pla-nar series-fed array are addressed to achieve beam steering with frequency tunability over a relatively broad bandwidth. The design is possible thanks to the use of the complementary strip-slot, which is an innovative broadly matched microstrip radiator, and the careful selection of the phase shifter parameters.

Single-Feed Dual-Band Circularly Polarised Microstrip Antenna

A novel technique for obtaining dual-hand circular polarization (CP) radiation of a single-feed circular microstrip antenna in proposed and demonstrated. By embedding two pain of arc shaped slots of proper lengths close to the boundary of a circular patch, and protruding one of the arc-shaped slots with a narrow slit, the circular microstrip antenna can perform dual-hand CP radiation using a single probe feed. Details of the antenna design

Circularly Polarized Compact Microstrip Antenna

A compact microstrip antenna with circular polarization radiation is demonstrated.A reducation in the required parameters for achieving CP radiation makes the present antenna design simpler

Slot coupled sqaure microstrip antenna for compact dual-frequency operation

A novel dual frequency design of a square microstrip antenna coaxially fed along the diagonal with a chip capacitor mounted at the bottom of the stub is introduced. This design provides enhanced area reduction and good cross-polarization levels. The antenna design can be used as a compact antenna system where limited size is a major requirement. The details of the antenna design and experimental results are presented