Effect of adhesive bonds on electrical performance in multi-layer composite antenna

We study experimentally the effect of adhesive bonds in a multi-layer composite antenna. Changes in the antenna performance after the bonding process were determined. Three types of antennas were designed and fabricated, with different resonant frequencies. The measured electrical performances of these fabricated structures reveal that all antennas undergo a fall in their resonant frequencies and a reduction in the gain. The change in resonant frequency is related to a change in the effective dielectric constant of the assembly, and the gain falls due to loss in the adhesive. Corrections were then introduced in the design process so as to compensate for the effect of the adhesive. The measured results for the modified antenna show excellent agreement with the target performance. (C) 2009 Elsevier Ltd. All rights reserved.X111620sciescopu

High-Efficiency Crossed-Loop 4G LTE Antenna for All Display Metal-Rimmed Smartphones

A symmetrically crossed-loop antenna featuring very high radiation efficiency across the entire LTE frequency bands for metal-rimmed smartphones with only 2 mm ground clearance is proposed, analyzed, and verified. The employment of even and odd modes is utilized to achieve wide bandwidth across 698–960 MHz (low-frequency spectrum), 1710–2170 MHz (middle-frequency spectrum), and 2300–2690 MHz (high-frequency spectrum). Empirical analysis confirms the crossed-loop topology results in a 180° phase shift of the electric current distribution on the ground plane, resulting in enhancement of the radiation resistance. As a result, the devised LTE antenna exhibits more than 48% to 75% total system efficiency across the entire band of interest, which is the highest efficiency reported in literature for metal-rimmed smartphones with extremely small ground clearance

Multilayer Effects on Microstrip Antennas for Their Integration With Mechanical Structures

Abstract—The effect of multilayer geometry on microstrip antennas is investigated for the design of antenna-integrated mechanical structure. Changes in the gain of antenna due to the geometry have been determined using a transmission line analogy. Design of high-gain antenna in bandwidth is proposed away from structural resonance. Experiments are done on microstrip antennas covered by superstrates in order to verify high-gain conditions theoretically derived herein. The off-resonant conditions that use practical materials of moderate thickness make it possible to design the antenna-integrated mechanical structure with the perfect integration of high mechanical and electrical performances. Index Terms—Composite structure, embedded antenna, gain enhancement, integrated antenna, mechanical structure. I

288 Hybrid Electrical/Mechanical Optimization Technique Using Time- Domain Modeling, Finite Element Method and Statistical Tools for Composite Smart Structures

(DOE) and Response Surface Methods (RSM) approaches in a simultaneous electrical and mechanical optimization study for a load-bearing antenna structure is presented. The benchmarking geometry is a stacked patch antenna integrated in a sandwich structure made of composite laminates and Nomex honeycomb. The antenna is electromagnetically modeled in time domain and it is found that, for the chosen geometry, the honeycomb structure improves the gain of the antenna without affecting the bandwidth. The structure is then optimized using the same experiment that integrates both the electrical and mechanical (calculated with finite elements) parameters of the system. The simple factorial design is very simple to implement and gives a clear understanding of the system behavior, including the interaction between the mechanical changes and electrical performance thus allowing the engineer to integrate, for the first time, both the electrical and mechanical features of the system in the same optimization technique. Index Terms- Time domain modeling, hybrid optimization, mechanical performance, composite smart structure

Four-element Reconfigurable Coupled Loop MIMO Antenna Featuring LTE Full Band Operation for Metallic-rimmed Smartphone

This paper describes a low-profile 2×2 Multi-Input Multi-Output (MIMO) antenna system that is fully functional over the entire Long-Term Evolution (LTE) spectrum 699–960 MHz (lower frequency spectrum) and 1710–2690 MHz (higher frequency spectrum) that is applicable to real-life metallic smartphone platforms. The presented methodology entails utilizing the longitudinal edges of the ground plane amid an extremely narrow ground clearance of 2 mm. The metallic frame of the smartphone is utilized along with a stub network to devise a reconfigurable coupled loop antenna topology. The proposed 2×2 MIMO antenna configuration is measured and confirmed to exhibit efficient Envelope Correlation Coefficient (ECC) (<0.5) and one of the highest radiation efficiencies to be reported in literature across the entire LTE spectrum.11Nsciescopu

mmWave 5G NR Cellular Handset Prototype Featuring Optically Invisible Beamforming Antenna-on-Display

The reduced link margins caused by undesired blockage such as the user&apos;s hand and inherent limitations of beamsteering angles for planar antenna components constitute one of the most critical challenges for future mmWave mobile devices. This underscores the need for a new beamforming antenna strategy, which can enhance the foreside coverage with minimum compromise. This article provides a detailed overview of an mmWave beamforming antenna concept denoted as an optically invisible antenna-on-display (AoD), which can enhance the CDF, especially in the foreside direction of mobile devices such as cellular handsets. In contrast to existing antenna component strategies, the AoD is integrated within the view area of high-resolution OLED or LCD display panels of cellular handsets while remaining unnoticeable to the human eye through the use of nano-scale patterns. This allows the realization of highly precise beamforming in the foreside direction for large-screen mobile devices. The fundamental phased-array AoD strategy is introduced and compared with existing mmWave 5G beamforming antenna strategies for mmWave 5G NR cellular handsets. The operating mechanism of the mmWave 5G phased-array AoD component and its integration with existing wireless component architectures and a 537 ppi density OLED panel are considered. This concept is further refined by integrating a series of fabricated 28 GHz phased-array AoD components within a real-life mmWave 5G NR Android-based cellular handset prototype reported in the literature for the first time. The foreside beamforming characteristics at 28 GHz are experimentally studied followed by investigation of OTA measured EVMs using QPSK, 16- and 64-QAM mmWave 5G NR waveform signals in accordance with the 3GPP requirement.11Nsciescopu

Circuit-on-Display: A Flexible, Invisible Hybrid Electromagnetic Sensor Concept Circuit-on-Display: A Flexible, Invisible Hybrid Electromagnetic Sensor Concept

There have been scarce interactions between microwave circuits and display technologies over the past few decades. However, the two share many similarities leaving room for integration and co-development. Hence, we present a Circuit-on-Display (CoD) concept that dually functions as a radio-frequency transceiver and a high-resolution touch screen display. The approach is realized through a flexible, invisible hybrid electromagnetic sensor (HEMS) which is situated inside a high-resolution display panel. The CoD is integrated within a real-life millimeter-wave 5G NR Android-based cellular handset prototype to demonstrate a foreside beamforming coverage and a touch operation with high-resolution and optimal image quality. The devised HEMS prototype independently features flexibility, optically invisibility (transmittance >88%), and multi-functionality (system gain of 20.72 dB, beam scanning range of ±40°, and mutual capacitance change ratio >4.42%). The devised approach provides a new class of approach to enable microwave integrated circuits for new generation wireless electronics.11Yothe