Polarization reconfigurable air-filled substrate integrated waveguide cavity-backed slot antenna

The Internet of Things requires highly efficient ultra-wideband antenna systems that yield high performance at low manufacturing cost. Therefore, a novel ultra-wideband circular air-filled substrate-integrated-waveguide (AFSIW) cavity-backed annular slot antenna is proposed that enables straightforward integration into general-purpose materials by means of standard manufacturing techniques. The cavity top plane, serving as antenna aperture, contains two concentric annular slots, both split into two by shorting tabs that create a virtual electric wall. This enables the generation of a TE11; slot even mode in both parts of each annular slot, giving rise to a conical radiation pattern. By exciting two such modes and judiciously positioning their resonance frequencies, all the unlicensed national information infrastructure (U-NII) [5.15-5.85] GHz radio bands are covered. The annular slot antenna is then made polarization reconfigurable through an innovative excitation of the slot modes by replacing the shorting tabs with four pairs of the PIN diodes. These dynamically switch between two orthogonal linear polarizations by changing the dc control current at the antenna RF port through an external bias tee. This simple, yet effective, bias network enables the integration of all polarization control electronics inside the antenna cavity to protect them from environmental effects. A low-cost antenna substrate was realized through standard additive manufacturing in a 3D-printed substrate, while a standard high-frequency laminate was used to implement the upper conducting plane containing the radiating elements and the polarization reconfiguration electronics. The antenna features an impedance bandwidth of 0.93 GHz, a front-to-back ratio of 14 dB, a total antenna effiency higher than 95%, and 4.9 dBi gain for each polarization state

Multipolarization-reconfigurable air-filled substrate integrated waveguide cavity-backed slot antenna

A novel single-feed ultrawideband cavity-backed slot antenna with a reconfigurable polarization capability is demonstrated in substrate-independent air-filled substrate integrated waveguide (AFSIW) technology for Internet-of-Things applications in the [5.15-5.85] GHz frequency band of the unlicensed national information infrastructure. The antenna achieves an ultrawide impedance bandwidth by exploiting a double ring of slots and supports four switchable linear polarization states (+/- 45 degrees, 0 degrees, +45 degrees, and 90 degrees) by leveraging four quartets of p-i-n diodes. By electrically shorting the slots at well-defined positions by these p-i-n diodes, dynamic polarization reconfiguration is achieved by switching their dc bias current, supplied at the antenna feed through an external bias tee and routed from the antenna's back to front cavity plane via the AFSIW sidewalls. This new simple, yet effective, bias network enables the integration of all polarization control electronics inside the antenna cavity to protect them from environmental effects. Finally, measurements prove that the prototype exhibits an overlapping impedance bandwidth of 29%, from 4.85 to 6.45 GHz, and a stable conically shaped radiation pattern across the operating bandwidth with a 3 dB beamwidth of 45 degrees and a peak gain of 6.5 dBi for all four states

A Review: Substrate Integrated Waveguide Antennas and Arrays

This study aims to provide an overview and deployment of Substrate-Integrated Waveguide (SIW) based antenna and arrays, with different configurations, feeding mechanisms, and performances. Their performance improvement methods, including bandwidth enhancement, size reduction, and gain improvement are also discussed based on available literature. SIW technology, which acts as a bridge between planar and non-planar technology, is a very favorable candidate for the development of components operating at microwave and millimeter wave band. Due to this, SIW antennas and array take the advantages of both classical metallic waveguide, which includes high gain, high power capacity, low cross polarization, and high selectivity, and that of planar antennas which comprises low profile, light weight, low fabrication cost, conformability to planar or bent surfaces, and easy integration with planar circuits

Dual-polarized 28-GHz air-filled SIW phased antenna array for next-generation cellular systems

A high-performance dual-polarized eight-element air-filled substrate-integrated-waveguide (AFSIW) cavity-backed patch antenna array is presented. The antenna operates in the [26.5-29.5] GHz band and provides a stable high data-rate wireless communication link between end-user terminals and access points in next-generation cellular systems. Its topology is carefully selected to maximize the performance of the array. In addition, by combining the AFSIW technology with a new antenna architecture, a low-profile, low-cost, stable, and high-performance array design is guaranteed. A prototype was fabricated and validated, demonstrating a wide active impedance bandwidth over ±35 o scanning range and low-cross polarization level within the entire frequency band

2009 Index IEEE Antennas and Wireless Propagation Letters Vol. 8

This index covers all technical items - papers, correspondence, reviews, etc. - that appeared in this periodical during the year, and items from previous years that were commented upon or corrected in this year. Departments and other items may also be covered if they have been judged to have archival value. The Author Index contains the primary entry for each item, listed under the first author\u27s name. The primary entry includes the coauthors\u27 names, the title of the paper or other item, and its location, specified by the publication abbreviation, year, month, and inclusive pagination. The Subject Index contains entries describing the item under all appropriate subject headings, plus the first author\u27s name, the publication abbreviation, month, and year, and inclusive pages. Note that the item title is found only under the primary entry in the Author Index

2008 Index IEEE Transactions on Control Systems Technology Vol. 16

This index covers all technical items - papers, correspondence, reviews, etc. - that appeared in this periodical during the year, and items from previous years that were commented upon or corrected in this year. Departments and other items may also be covered if they have been judged to have archival value. The Author Index contains the primary entry for each item, listed under the first author\u27s name. The primary entry includes the coauthors\u27 names, the title of the paper or other item, and its location, specified by the publication abbreviation, year, month, and inclusive pagination. The Subject Index contains entries describing the item under all appropriate subject headings, plus the first author\u27s name, the publication abbreviation, month, and year, and inclusive pages. Note that the item title is found only under the primary entry in the Author Index

Liquid Metal Reconfigurable Antennas

This thesis work is focused on the investigation of reconfigurable antennas enabled by non-toxic liquid metal, Eutectic Gallium Indium (EGaIn). The research goal is to demonstrate the integration of emerging additive manufacturing techniques and liquid metal fluidic systems in the design of reconfigurable antennas. Three antennas have been built to demonstrate the utility of EGaIn, capability of additive manufacturing techniques, and integration of an antenna to a low cost PCB with readily available fabrication process. The first antenna is a polarization reconfigurable slot antenna backed by circular substrate integrated waveguide cavity that uses EGaIn in a microfluidic channel to change its polarization by changing the position of the aperture. The second antenna is a frequency reconfigurable dipole antenna that uses EGaIn as a radiating element to change its resonance frequency by contracting and expanding the length of EGaIn. The third antenna is a polarization reconfigurable cross patch antenna that uses EGaIn as a switch to alter its polarization. It is found that the actuation of the EGaIn in a micro-vascular channel largely depends on the size of the channel if pressure driven method is used. Incorporating EGaIn in an antenna design is capable of producing unique and versatile functionalities, and EGaIn is well suitable for reconfigurable antenna design like the ones demonstrated in this thesis work

인체통신용 안테나에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2015. 2. 남상욱.This thesis presents the antennas for in-body, on-body communication. The antennas in body communication are severely affected by human body which has a high relative permittivity and conductivity. The high relative permittivity and conductivity degrades the antenna bandwidth and efficiency. Therefore, it is a main challenge that enhancing the bandwidth and the efficiency of the antenna maintaining the small size. In order to enhance the performance of the antennas several techniques are proposed in body communication antennas. Firstly, the Q value and the efficiency of the in-body antenna are investigated. Using the proposed equations, the optimum frequency of the in-body antenna will be given. To maximize the antenna dimensions in the endoscopy antenna, the outer wall loop antennas is proposed. The measurement results are given to show the performance of the proposed antenna. Secondly, the several techniques for on-body antenna are proposed. The conventional antennas without the ground plane like dipole and slot antennas are not appropriate for on-body environment because the body has low intrinsic impedance and high conductivity compared to that of the free space. Therefore, antennas with ground plane like patch and cavity-backed slot antennas are proposed for on-body communication. The cavity-backed slot antenna with via-hole above the slot is proposed for bandwidth enhancement of the antenna. As the place of the via-hole introduces the additional resonance, wider bandwidth is achieved. The substrate removal technique for cavity-backed slot antenna is also proposed for the bandwidth and the efficiency enhancement. The removal of the substrate across the slot decreases the Q of the antenna, increasing the bandwidth and efficiency. In addition, the folded-cavity-backed slot antenna is given for size miniaturization of the cavity-backed slot antenna. The folded structure of the proposed antenna increases the effective length of the antenna, decreasing the antenna resonance frequency. Furthermore, the reconfigurable shorted patch antenna is given for wide bandwidth. Lastly, the dual-band and dual-impedance cavity-backed slot antennas are given for the efficient on-body systems1. Introduction 1 1.1 WBAN (Wireless Body Area Network) Applications 1 1.2 Electrical Properties of Human Body 5 1.3 Challenges in Designing Body Communication Antenna 7 2. Antennas in Human Body 10 2.1 Properties of the Antenna in Human Body 10 2.1.1 Radiation efficiency of the Antenna in Human Body 11 2.1.2 Q of the Antenna in Human Body 14 2.1.3 Numerical Results and Conclusion 15 2.2 Outer-Wall Loop Antenna for Capsule Endoscope System 18 2.2.1 Introduction 18 2.2.2 Antenna Design 20 2.2.3 Simulation and Measurement results 23 2.2.4 Conclusion 31 3. Antennas on human body 32 3.1 Properties of the Antenna on Human Body 32 3.1.1 Model of the Human Body 32 3.1.2 Antennas without Ground on Human Body 34 3.1.3 Antennas with Ground Plane on Human Body 36 3.2 Cavity-backed slot Antenna on Human Body 38 3.2.1 Operation of Cavity-backled Slot Antenna 38 3.2.2 Bandwidth and Efficiency Enhancement using Substrate Removal 40 3.2.3 Bandwidth Increase using Via-hole above the Slot 54 3.2.4 Miniaturization using Folded Cavity Structure 66 3.2.5 Dual-band Technique for Slot Antennas 81 3.2.6 Dual Impedance Cavity-backed Slot Antenna 86 3.3 Shorted Patch Antenna on Human Body 97 3.3.1 Operation of Shorted Patch Antenna 98 3.3.2 Reconfigurable Shorted Patch Antenna 100Docto

A Novel SIW Cavity-Backed Cork Antenna Reconfigurable in Polarization through Feed-Line Bias

In this thesis, a novel SIW cavity-backed antenna reconfigurable in polarization in a huge frequency band, based on a cork substrate, is discussed. The polarization reconfigurability is achieved by means P-i-N diodes properly biased applying a certain current on the coaxial cable. Making an antenna reconfigurable allows the design to be generic and suitable for various applications. Furthermore, an additional layer on the top of the antenna is avoided and this reduces the amount and length of interconnections needed, improving the reliability