Optimum Design of Low-Cost Dual-Mode Beam- Steerable Arrays for Customer-Premises Equipment Applications

Two novel designs of dual-mode beam-steerable array antennas are proposed for customer- premises equipment applications. To obtain the optimal distribution of excitations for the arrays, the gain and front-back ratio of the array systems are optimized by using the method of maximum power transmission efficiency. The first design operates at 2.45 GHz and uses four folded monopoles of height<1/10 wavelength and a sleeve of height of 1/4 wavelength underneath the monopoles. The peak gain and the front-to-back ratio are 6.7 dBi and 7.8 dB respectively. The second design operates at 830MHz and uses four Yagi monopoles as elements with a common reflector and four directors. The peak gain and the front-to-back ratio for the second design are 6.0 dBi and 16.8 dB respectively. The proposed antennas have advantages including: low cost and compact size; dual-mode operation including the modes of omnidirectional radiation and directional radiation; and in the mode of directional radiation, the beam can be electronically steered to achieve the full coverage of the azimuthal plane. It achieves higher gain than the traditional electronically steerable passive array radiator antenna

Integrated Design of Wideband Omnidirectional Antenna and Electronic Components for Wireless Capsule Endoscopy Systems

This paper presents a wideband antenna with omnidirectional radiation pattern for wireless capsule endoscopy (WCE) systems. The proposed antenna radiates as a slot structure formed between a central copper cylinder and a copper strip attached to the interior surface of biocompatible polyimide shell. Main features of the antenna include: 1). An integrated design of the antenna and electronic components in the capsule is employed. And, by utilizing the entire inner space of the capsule, the radiating aperture of antenna is increased to the maximum; 2). The copper cylinder can be used to house electronic components, therefore the potential electromagnetic interferences (EMI) brought by battery and electronic circuits are reduced to the minimum; 3) The antenna in tissue has a wide bandwidth from 0.721 to 1.705 GHz, covering both 0.902-0.928 GHz Industrial, Scientific, and Medical (ISM) band and 1.395-1.4 GHz Wireless Medical Telemetry Service (WMTS) band. This is achieved by optimizing the stepped width of copper strip; 4). The antenna inside human tissues has stable omnidirectional radiation patterns across all operating frequencies. This is an indispensable characteristic due to the unpredictable orientation of capsule in the gastrointestinal (GI) tract. Stable patterns are achieved by having strong electric fields concentrated within the top substrate pointing at the same direction. The integrated design concept, wideband impedance matching and stable omnidirectional radiation patterns make the proposed antenna a promising candidate for future WCE system

Ultra-wideband and Multiband Reflectarrays for Intelligent Multi-functional Platforms

This paper includes two parts. In the first part, a review of techniques for designing wideband or multiband reflectarrays is presented. In the second part, two case studies including the designs of one ultra-wideband (UWB) reflectarray and one multi-band reflectarray are presented. The UWB reflectarray is a novel tightly coupled dipole reflectarray (TCDR) whose unit cell is composed of a tightly coupled dipole and a delay line. The minimum distance between adjacent cells is about 1/10 wavelength at the lowest operating frequency. The TCDR operates from 3.4 to 10.6 GHz with stable radiation patterns and aperture efficiency. The multiband reflectarray is a novel dual-band, dual circularly polarized (CP) reflectarray. The dual-band operation of the reflectarray is obtained by using the interleaved circularly polarized triangular patches as the radiating elements. Within each frequency band, two simultaneous shaped beams with different circular polarization and independent control are realized. Both reflectarrays are fabricated and measurement results are presented

Broadband Circularly Polarized Filtering Antennas

This paper consists of two parts. The first part presents a review of the recent development in broadband circularly polarized filtering antennas. The second part presents a novel design of broadband integrated filtering antenna based on eighth-mode SIW (EMSIW) resonators for rectenna applications. This work has three main novel contributions. First, by adjusting the external quality factors and coupling coefficients of the resonators in this filtering antenna, optimum input impedance with a complex value can be realized within the filtering antenna. Thus there is no need for an external impedance matching network, which is usually required between the antenna and the rectifying circuits; Second, compared with traditional microstrip resonators, high-Q EMSIW cavities are used to increase antenna gain; third, the coupling gap between the EMSIW resonators also acts as the feeding structure of the radiator. So the feeding structures are all on the middle layer. The ground plane on the back side is a complete structure without any defects. This novel structure design improves front-to-back ratio to enhance the antenna receiving efficiency. To validate this method, two C-band circularly polarized integrated filtering antennas with an input impedance of 50 $\Omega$ and complex impedance are designed, simulated, and fabricated. The measured results show that the operating frequency bandwidth of the proposed antennas is more than 14.5% at C-band with the gain above 8 dBi. The 3-dB axial ratio bandwidth is larger than 8.5% and the front-to-back ratio is higher than 18 dB. Moreover, the proposed antenna with complex impedance is conjugate matched with the input impedance of a specific rectifying circuit at 5.8 GHz and harmonics suppression at the second-harmonic frequency is achieved

Wideband high-gain millimetre/submillimetre wave antenna using additive manufacturing

This paper presents a novel design of a wideband high-gain resonant cavity antenna (RCA) for millimetre and submillimetre wave bands, and its fabrication using additive manufacturing. The proposed RCA antenna consists of a partially reflecting surface and three impedance matching layers fed by a waveguide. Additive manufacturing (AM) techniques are utilized to fabricate the design operating at 30 GHz. Two fabrication techniques are assessed for printing the antenna. The first technique is based on printing a dielectric material and fully coating the parts with a metallic layer, while the second technique involves printing the parts in a single process using metal 3D printing. The first technique offers a lightweight solution while the second technique can print the whole model in one run. The antenna design is investigated by both simulations and experiments. The measured results show an 3dB gain bandwidth of about 10%, and high gain over 15 dBi for all the three resulting antennas. Good agreement between simulation and measurement is obtained. The antenna has a low cost and achieved good performance in terms of wide bandwidth and high gain, thus it is potentially useful for highspeed wireless communications at millimetre-wave and sub-millimetre-wave frequencies

Foundations of Applied Electrodynamics

Foundations of Applied Electrodynamics takes a fresh look at the essential concepts and methods of electrodynamics as a whole, uniting the most relevant contemporary topics under a common mathematical framework. It contains clear explanations of high-level concepts as well as the mutual relationships between the essential ideas of electromagnetic theory. Starting with the fundamentals of electrodynamics, it methodically covers a wide spectrum of research and applications that stem from electromagnetic phenomena, before concluding with more advanced topics such as quantum mechanics.:; Include