Experimental Comparison of Small Wideband Magnetic Loops

Electronics and Communications in Japan (Part I: Communications), 1998

Small receivers such as pagers are used in various situations due to their portable nature. These portable units are subject to changes in situation and shift of location so that the receiving gain of arriving wave changes significantly. In this paper, the characteristics of planar loop antennae are studied in detail. We proposed that polarization characteristics can be improved significantly by switching the shorting location of the planar loop antenna. In order to study this effect more realistically, polarization characteristics are measured and evaluated using a model that includes a switching circuit and an oscillator. ©1998

Advanced Science and Technology Letters, 2013

This paper is a study of rectangular wire loop antenna at different side ratios using EZNEC+ v5.0 simulation software. Four wire diameters are considered. The rectangular antenna is configured at two different perimeter lengths. One length was 1-λ long, and the other is resonant length at square configuration. Effects to impedance, return loss and standing wave ratio are considered. The best positive combination of these parameters in a single side ratio is resolved. Recommendation for direction of follow up study is included.

International Journal of Electrical and Computer Engineering (IJECE), 2024

This paper proposes a new large loop antenna with a reduced magnetic field for a near field communication (NFC) target used in a metallic environment. It also defines a fairly clear method for controlling and, more specifically, reducing the magnetic field associated with loop antennas. This antenna consists of a circular winding, inside which we insert a square winding arranged in the shape of a diamond. The particular structure of this antenna shows that it is possible to dissociate the increase in the induced magnetic field, linked to its large size, from the increase in the number of windings. This is made possible by the application of the physical principle of overlapping magnetic fields, which results in partially destructive interference.

The problem of a finite, ferrite-rod antenna has been treated theoretically by recognizing an analogy between the ferrite antenna. and the conducting cylindrical dipole antenna which has been studied extensively. Initially the ferrite is idealized to be a perfect magnetic conductor and an Hall~n type of integral equation (1] is obtained for the magnetic current. By allowing the antenna height to approach infinity, the formulation is shown to be consistent with previously obtained results for the infinitely long ferrite antenna [2]. Subsequently, the integral equation is modified appropriately to treat the ferrite as an imperfect magnetic conductor, and the current is obtained in the three-term form of King and Wu (3]. Because this treatment relies rather heavily on a mathematical equivalence of the two problems under idealized driving conditions, an alternative, more rigorous formulation is presented. The result is a pair of coupled integral equations in the tangential electric field (or magnetic current) and the circumferential electric current. The coupled integral equations are solved numerically. An experimental apparatus was fabricated to verify the solutions. Good agreement is obtained for a range of parameters. 11te experiments were performed for three values of 0-2 Ln(2h/a)-8.5534, 7.4754 and 6.089. The electrical radius ak 0 ranged from .00132 to .01662.

Asian Journal of Scientific Research, 2011

2012 6th European Conference on Antennas and Propagation (EUCAP), 2012

Figure 1. Loaded loop unit cell.

Journal of King Saud University - Engineering Sciences, 2011

A multiband loop antenna that consists of a strip loop with two L-shaped arms connected together and designed to share the same feed and shorting points is introduced. In particular, this design can be considered to be an enhancement to the antenna presented in Chi and Wong (2007). The proposed antenna has sufficient bandwidth which makes it suitable for Global System for Mobile (GSM) in the 900 MHz band, it also supports effectively the Advanced Mobile Phone Systems (AMPS) 824-894 MHz, and the Digital Communication Systems (DCS) 1900 MHz bands with 2.5:1 VSWR. As in Alkanhal (2005), the chip-resistor loading technique was investigated by introducing a 3 X resistor to the antenna instead of the shorting pin between the antenna and ground. This paper presents simulation results, detailed design, and parametric study with analytical discussion for the proposed antenna.

2015

As a natural sequel to an earlier presentation (1), which compared the performance features of equal perimeter circular- and square-loop antennas located over flnite ground planes, this paper, using the same formulation, examines the same performance characteristics, but this time, with the antennas being of equal cross-sectional areas; and with loop heights varying between 0.05‚ and 1.00‚ at the operating (center) frequency of 1.25GHz. Computational results for the antennas' input characteristics reveal that whereas they share virtually identical input resistance proflles, input reactance for the square loop has values that are in general, lower than those for the circular loop, for the entire range of 'height above ground plane' considered. Results for the E- and H-plane radiation fleld patterns indicate that when the loops are located at heights beyond 0.3‚ above the flnite ground plane, the front-lobes become distorted; an observation supported by the proflles of the...

We present in this work a loop-type planar antenna with compact, simple geometry and broadband features. The commercial softwares CST Microwave Studio and Zeland IE3D were used in the simulations and optimization of this antenna. The optimization was made for the input return loss bandwidth by varying the antenna geometric parameters. The antenna has 72 % bandwidth for a 10 dB input return loss, with a relatively flat gain within the operating bandwidth.

HELIX, 2018

In this paper, a printed loop antenna with current reconfiguration technique is proposed to improve the usability of the loop as a multiband antenna for UWB applications ranging from 3.1 GHz to 10.6 GHz. The current reconfiguration is achieved using a capacitive gap along the circumference of the loop antenna. The shift in the location of the capacitive gap changes the current distribution in the antenna and new bands are generated. It is found that using a single capacitive gap along the loop, the antenna can be operated as a wide band antenna whose frequency ranges from 6 GHz to 10.8 GHz with % bandwidth of 57. The proposed loop can also be used as dual and triple band antenna in the frequency range from 6 GHz to 10.8 GHz by simply switching ON and OFF the switches. The proposed antenna generates the highest numbers of bands at the minimum expense of switches. The proposed loop without capacitive gap is capable of covering only 24% out of the 3.1 GHz-10.6 GHz range. The range of band can be varied from 24% to 57% using the switches. The proposed antenna very well rejects the WLAN and WiMAX bands.