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A novel pattern reconfigurable (PR) antenna is proposed. The PR antenna is composed of a pair of dipole elements. Each dipole element consists of a folded dipole, a short dipole and a parasitic element. A broadband balun with two pin-diode switches is utilized to feed the antenna. By changing the states of the switches, the radiation patterns can be reconfigured in two opposite directions. The PR...
The crossed dipole is a common type of antenna that is used to generate circularly polarized radiation in a wide frequency range. This antenna was originally developed in the 1930s and today is used in many wireless communication systems, including broadcast services, satellite communications, mobile communications, global navigation systems satellite system (GNSS), radio frequency identification...
In this paper, the goal is to investigate the properties of the reflection coefficient of lossless antennas using sum rules. We study different bandwidth bounds derived from sum rules, and apply them to a few antennas. We also estimate the size of the correction terms of the sum rules for this case. Thereafter, we test the bounds on resonant and wide band antennas.
This paper discusses the results of an ongoing study aimed at the miniaturization of a dual linearly polarized crossed dipole antenna at 7 MHz, which can be used for near vertical incidence skywave (NVIS) communication. The goal is to achieve 24 kHz bandwidth and −10 dBi gain when placed on a vehicle. It is shown that the requirements are met with a 3 m long (λ/14) inverted V crossed dipole placed...
Antennas formed by a single cylinder with a longitudinal slot are presented. It has been shown that the antennas allow flush installation and can be efficiently used either as a single radiating element or as an element in antenna arrays. Physical phenomena that were utilized to produce uniform field distribution along the slot and as the consequence, to create optimal directivity, have been studied.
Design and simulation of a conformai high impedance surface with spherical curvature is reported. A loop antenna is located in the vicinity of this curved surface to investigate if the spherical HIS can be used as an appropriate ground plane. The return loss and gain pattern of the loop is obtained from simulations and compared with those of a flat circularly symmetric HIS. The −10 dB operational...
In this paper, we investigate the feasibility of substantial bandwidth enhancement of a low-frequency miniaturized antenna on a robotic flyer through magnetic coupling with similar elements in a tight flight formation. The dimensions of a single radiating element are confined to within λ/10 × λ/10 × λ/10 for operation at around 300 MHz. Variations of end-loaded meandered line dipoles are studied and...
A broadband linearly polarized magnetoelectric (ME) dipole antenna with broad beamwidth in both E-plane and H-plane is presented. By employing four L-shaped dipole arms and inclined sidewalls along the E-plane edge of the ground plane, wide half power beamwidth of 100 ± 6 ° and wide pattern bandwidth from 1.9 to 2.7 GHz are obtained, as well as nearly identical E-plane and H-plane radiation patterns...
The paper proposes a differential feeding network with arbitrary frequency-dependent phase difference between the output ports. This network consists of a power divider, a C-section phaser and a TEM transmission line. It is applied to enhance the axial ratio bandwidth of circularly polarized antennas. A design example is provided and the result shows that the axial ratio bandwidth is largely improved...
Thin form factor and placement-insensitivity are essential qualities of planar RFID antennas. Placement insensitivity can be achieved by introducing a conducting back plane. As the antennas become thinner, most of the energy is stored in the form of parallel plate modes resulting in the reduction of the bandwidth. Edge treatment in the form of serrations can be used to improve the bandwidth of such...
This paper presents a miniaturized ultra wideband UHF antenna. The antenna is loaded with magneto dielectric material. The antenna consists of a bent dipole backed by a magneto dielectric loaded reflector. The input impedance of the antenna is matched with 50 ohm cable by adopting a special technique that increases the cable impedance gradually to 73 ohm. The antenna is backed by a magneto dielectric...
In this paper, a development of compact T-shaped dipole antenna is investigated for Ground Positioning System (GPS) application. The proposed antenna is equipped by a balance-to-unbalanced (balun) circuit to transform the antenna into the unbalance circuit feedable from a coaxial cable. The balun circuit is made of a λ/4 element which is also used as a stand of the antenna. Prior to fabrication, the...
This paper presents the step-by-step design procedure and simulated performance investigation of a printed log-periodic dipole antenna (LPDA) that is able to operate cover wide frequency range (800–2500 MHz). The advantage of this antenna is compact and easy to integrate with planar circuits which is suitable for applications that need wide bandwidth and high gain antenna. The dimension of designed...
In this paper, the performance comparison of an existing slot dipole flexible bendable antenna is carried out with a newly modified design, featuring balanced size miniaturization for implantable wireless communications. By introducing a minuscule dimension along with the use of low cost substrate and patch material, this proposed antenna has a heightened reliability and feasibility in turns of performing...
A novel beamwidth reconfigurable antenna is presented. The design methodology uses tunable strip gratings placed on the sides of a magneto-electric (ME) dipole along its H-plane. A fully functional prototype with an as wide as 40% impedance bandwidth (for SWR ≤ 1.5) is developed and tested, demonstrating the H-plane beamwidth with a tuning range from 81° to 153°. With the wide beamwidth variation...
This paper presents the antenna for ground penetrating radar (GPR) for soil characteristics measurement application. The objective is operating frequency having range from 250–1250 MHz whilst restricting antenna lobs radiate to ground direction. The demand of ground penetrating radar design is antenna with ultra wide bandwidths (UWB). Designing optimum gain consideration of 5dBi thus the conventional...
A novel, dual-mode planar circularly polarized (CP) antenna with an end-fire radiation beam in parallel with its plane is proposed and numerically investigated. The antenna consists of an aperture and a printed dipole. A pair of stubs are unilaterally loaded along the dipole, and used to generate a dual-mode radiation characteristic. As simulated, it is observed that the impedance bandwidth (20log|S11|...
A novel planar end-fire circularly polarized (CP) complementary antenna is presented. It consists of an aperture element as the magnetic dipole and a printed dipole element as the electric dipole. Due to the combination of the vertically polarized component from a magnetic dipole and the horizontally polarized component from a printed dipole on the same substrate, a planar CP antenna with end-fire...
An ultra-wideband (UWB) Tightly Coupled Dipole Array (TCDA) composed of a horizontal inter-digital electric dipole and two WAIM layers is designed. The antenna is excited by a pair of 50Ω coaxial lines feed. A prototype was simulated. Results show that a bandwidth more than 5.7:1, with VSWR ≤ 3 from 2.4GHz to 13.6GHz, was achieved. The angle of scanning ranges up to 55° in E-plane while 50° in H-plane.
Understanding the impact of interference upon the performance of a multiple input multiple output (MIMO) based device is of paramount importance in ensuring a design is both resilient and robust. In this work the effect of element-element interference in the creation of multiple channels of a wireless link approaching the near-field regime is studied. The elements of the 2-antenna transmit- and receive-arrays...
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