Abstract-This paper proposes a new mobile handset antenna structure to reduce the value of the specific absorption rate (SAR). The antenna is based on the PIFA structure and operates at dual-bands of 0.9 GHz and 1.8 GHz. The chassis current is reduced using a metallic shim-layer inserted between the patch and chassis. This shim-layer is connected to the handset chassis through posts whose number and positions are determined using optimization techniques. Sidewalls are attached to increase the gain of the antenna and reduce the radiation towards human head. Simulations in the cheek mode show that the SAR reduction factor (SRF) of the proposed structure averaged over 10-g is more than 75% at 0.9 GHz and 46% at 1.8 GHz. The SRF values obtained using simulations and measurements are found to be better than 51% and 76% at 0.9 GHz and 1.8 GHz, respectively.
A novel technique to periodically modulate the aperture of a coupled mode leaky coaxial cable (LCX) is presented in this communication. The surface wave (monofilar mode) over the cable is modulated by periodically slotted aperture, converting it to a leaky wave. This leaky wave due to periodic modulation complements the leaked bifilar mode, thus enhancing the radiation efficiency of the LCX. The numerical results obtained through CST simulation are presented to prove the co-existence of a complex surface wave and a leaky wave over the surface of periodically modulated cable. As a proof of concept, a periodically slotted LCX operating at 4.5 GHz is designed and fabricated. Parametric studies are performed to observe the influence of the key parameters on the radiation performance. The measured results reasonably agree with the simulations.
Abstract-This paper presents the simulated results of a leaky coaxial cable antenna (LCXA) based on sinusoidally modulated reactance surface (SMRS). The theory of SMRS is employed to transform the leaky coaxial cable (LCX), a uniformly radiating structure into a directional antenna, LCXA. It is shown that high gain and arbitrary direction of radiation could be achieved by LCXA. . In its conventional application site, mines and tunnels, the uniformly radiating nature is an advantage over the conventional antennas but in different scenario like buildings and warehouses, it lacks the ability to sufficiently cover the space. It is due to the hybrid spatial nature of the indoor places, mix with long corridors, halls and rooms. KeywordsIn this communication, we present a novel LCXA design based on the sinusoidally modulated reactance surface (SMRS). The application of the SMRS theory transforms the radiation characteristics of the LCX. An arbitrary direction of radiation could be achieved through a judicious design of the reactance surface. The modulated reactance is achieved by periodically varying the length of the slots across the cable as show later in the paper.To improve the radio coverage at indoor places, we propose a solution to hybrid the LCX with LCXA sections in order to have directional radiation at required locations.
A dual-band dual-polarized antenna suitable for 5G millimeter-wave base station antenna array is presented in this paper. It operates on all the commercial millimeter wave frequencies allotted in 5G NR from 24.25 GHz up to 40 GHz. The antenna is based on a novel stacked square ring patches arrangement to achieve wide dual band and stable radiation pattern. The antenna offers a sharp roll-off and a filter like response between the operating bands due to the strongly coupled resonators. Antenna design principle and simulated performance are discussed in detail. The-10 dB impedance bandwidth of the lower band starts from 24.25 GHz to 29.5 GHz while the higher band covers the 37 GHz to 40 GHz. The realized gain remains stable between 5 to 6 dBi at all the operating frequencies. The isolation between the ports and cross-polar discrimination remain better than 20 dB in all the covered frequency range.
This article proposes a wideband differentiallyfed dual-polarized magnetoelectric (ME) dipole for millimeterwave (mm-Wave) applications. Various electric and magnetic characteristic modes of a slotted patch antenna are investigated and utilized effectively to create a stable broadside radiation pattern, covering 5G frequency bands from 24.25 GHz to 40 GHz. To implement this, the lifted ground (LGND) concept is applied to achieve a 57.1% impedance bandwidth for a single antenna element. Additionally, the three resonances of the antenna can be manipulated independently. The use of differential feeding allows more than 36 dB of port-to-port isolation across the entire operating band. The measured gains of the single element and 2×2 array are 8.4 dBi and 13.4 dBi, respectively. Also, the measured results indicate symmetrical E-and H-plane radiation patterns and cross-polarization levels lower than -26 dB. With the favorable electrical performance, compact size, simple structure and low-cost fabrication, the proposed ME dipole is a promising candidate for mm-Wave Antenna-in-Package (AiP) applications.
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