scholarly journals Comparing simulated results of folded and unfolded log-periodic antenna used for observing the Sun

2019 ◽  
Vol 5 (2) ◽  
pp. 49-54
Author(s):  
Ли Ша ◽  
Li Sha ◽  
Йан Йихуа ◽  
Yan Yihua ◽  
Чень Чжицзюнь ◽  
...  
Keyword(s):  
Antenna Array ◽  
Frequency Band ◽  
Antenna Arrays ◽  
Return Loss ◽  
Low Frequency ◽  
High Gain ◽  
The Sun ◽  
Wide Bandwidth ◽  
Impedance Characteristics ◽  
Log Periodic Antenna

There are two antenna arrays located in Mingantu Spectral Radio Heliograph (MUSER). MUSER-I and MUSER-II cover the frequency band ranging from 0.4 to 2 GHz and from 2 to 15 GHz respectively. A third antenna array covering 30–240 MHz will be established in the coming years. A log-periodic antenna is one of the choices for MUSER low frequency band; it radiates structures capable of maintaining consistent impedance characteristics over a wide bandwidth. Due to the ability of achieving high gain, it is widely used in many broadband applications. In this program, folded and unfolded log-periodic antennas are simulated for the Meridian project. In order to improve its return loss, this antenna is optimized with the width of each pole and the height of the substrate. This optimized process has been implemented in the simulated software HFSS.

scholarly journals Comparing simulated results of folded and unfolded log-periodic antenna used for observing the Sun

2019 ◽  
Vol 5 (2) ◽  
pp. 45-49
Author(s):  
Ли Ша ◽  
Li Sha ◽  
Йан Йихуа ◽  
Yan Yihua ◽  
Чень Чжицзюнь ◽  
...  
Keyword(s):  
Antenna Array ◽  
Frequency Band ◽  
Antenna Arrays ◽  
Return Loss ◽  
Low Frequency ◽  
High Gain ◽  
The Sun ◽  
Wide Bandwidth ◽  
Impedance Characteristics ◽  
Log Periodic Antenna

There are two antenna arrays located in Mingantu Spectral Radio Heliograph (MUSER). MUSER-I and MUSER-II cover the frequency band ranging from 0.4 to 2 GHz and from 2 to 15 GHz respectively. A third antenna array covering 30–240 MHz will be established in the coming years. A log-periodic antenna is one of the choices for MUSER low frequency band; it radiates structures capable of maintaining consistent impedance characteristics over a wide bandwidth. Due to the ability of achieving high gain, it is widely used in many broadband applications. In this program, folded and unfolded log-periodic antennas are simulated for the Meridian project. In order to improve its return loss, this antenna is optimized with the width of each pole and the height of the substrate. This optimized process has been implemented in the simulated software HFSS.

scholarly journals Design of a Multiband Antenna for LTE/GSM/UMTS Band Operation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Youngtaek Hong ◽  
Jinpil Tak ◽  
Jisoo Baek ◽  
Bongsik Myeong ◽  
Jaehoon Choi
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Return Loss ◽  
Low Frequency ◽  
Loop Antenna ◽  
High Frequency Band ◽  
Wide Bandwidth ◽  
Branch Line ◽  
Multiband Antenna ◽  
Additional Branch

This paper proposes a multiband antenna for LTE/GSM/UMTS band operation. The proposed antenna consists of a meandered planar inverted-F antenna with an additional branch line for wide bandwidth and a folded-loop antenna. The antenna provides a wide bandwidth to cover the hepta-band LTE/GSM/UMTS operation. The measured 6 dB return loss bandwidth is 169 MHz (793–962 MHz) at the low-frequency band and 1030 MHz (1700–2730 MHz) at the high-frequency band. The overall dimension of the proposed antenna is 55 mm × 110 mm × 5 mm.

scholarly journals A Large Decametric Wavelength Antenna Array for IPS Observations of Radio Sources

1980 ◽  
Vol 91 ◽  
pp. 403-403
Author(s):  
Ch. V. Sastry
Keyword(s):  
Solar Wind ◽  
Antenna Array ◽  
Low Frequency ◽  
Antenna System ◽  
Radio Sources ◽  
The Sun ◽  
Low Frequencies ◽  
Interplanetary Scintillations

Most observations of interplanetary scintillations of radio sources are made at frequencies around 80 MHz. These observations are limited to regions close to the sun, where the scintillations are maximum at this frequency. It is possible to extend these observations to the weakly scattering regions beyond 1 A.U. by making measurements at low frequencies. We have built a low frequency antenna system at Gauribidanur, India (Lat. 13° 36′ N and Long. 5 hrs. 10 min.), which can be used for this purpose. Although this system will not be dedicated to IPS, we intend to use it exclusively for solar wind observations during periods of interest.

scholarly journals Design of Wideband Slot Antenna Array with Stereoscopic Differentially Fed Structures

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Guang Sun ◽  
Ge Gao ◽  
Tingting Liu ◽  
Yi Liu ◽  
Hu Yang
Keyword(s):  
Antenna Array ◽  
High Gain ◽  
Radar System ◽  
Slot Antenna ◽  
Impedance Bandwidth ◽  
Antenna Element ◽  
Radiation Characteristics ◽  
Wide Bandwidth ◽  
Feeding Structure

In this paper, a wideband slot antenna element and its array with stereoscopic differentially fed structures are proposed for the radar system. Firstly, a series of slots and a stereoscopic differentially fed structure are designed for the antenna element, which makes it possess a wide bandwidth, stable radiation characteristics, and rather high gain. Moreover, the stereoscopic feeding structure can firmly support the antenna’s radiation structure and reduce the influence of feeding connectors on radiating performance. Secondly, a 4 × 4 array is designed using the proposed antenna element. And a hierarchical feeding network is designed for the array on the basis of the stereoscopic differentially fed structure. For validation, the antenna element and 4 × 4 array are both fabricated and measured: (1) the measured −10 dB impedance bandwidth of the antenna element is 62% (6.8–12.9 GHz) and the gain within the entire band is 5–9.7 dBi and (2) the measured −10 dB impedance bandwidth of the array is approximately 50% (7 to 12 GHz) with its gain being 14–19.75 dBi within the entire band. Notably, measured results agree well with simulations and show great advantages over other similar antennas on bandwidth and gain.

scholarly journals Experimental study on improving the accuracy of marine gravimetry by combining moving-base gravimeters with GNSS antenna array

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Zhimin Shi ◽  
Junjian Lang ◽  
Xinghui Liang ◽  
Zhibo Zhou ◽  
Aizhi Guo ◽  
...  
Keyword(s):  
Antenna Array ◽  
Real Time ◽  
Frequency Band ◽  
Antenna Arrays ◽  
Measurement Errors ◽  
Measurement Accuracy ◽  
Tectonic Activity ◽  
Gravity Measurement ◽  
Vertical Position ◽  
Point Positioning

AbstractThe gravity field is one of the Earth’s basic physical fields. The geoid can be calculated and the tectonic activity underground can be inversed by gravity anomaly. With the development of various ship-borne gravimeters and navigation technology, including the Global Navigation Satellite System (GNSS) and Strapdown Inertial Navigation System (SINS), the precision of marine gravimetry has been significantly improved (achieve or better than 1mGal). Errors arising from calculations of the correction term have become the main source of gravity measurement errors. At present, the traditional approach is to deploy a GNSS antenna, connect the GNSS antenna to the gravimeter, record the real-time position through data acquisition software, and then use this position to calculate the gravity correction item afterward. Two errors are inevitable. (1) The GNSS antenna position error is large. The pseudorange point positioning method is generally used to obtain real-time GNSS antenna positions, and the positioning accuracy is poor compared with that of precise point positioning. (2) The position coordinates of the gravimeter contain systematic errors related to the ship’s attitude. In this paper, a joint experiment including GNSS antenna arrays and ship-borne gravimeters was designed to evaluate the measurement accuracy via repeat lines on the same ship. The experimental results show the following: (1) attitude accuracies of 0.0299° for the yaw angle, 0.0361° for the pitch angle, and 0.1671° for the roll angle can be obtained at baseline lengths of 25 and 4 m. (2) The GNSS antenna array has an obvious role in determining the point acceleration in the low-frequency band (0–0.01 Hz) and the point position and velocity in the high-frequency band (0.01–1 Hz). (3) The vertical position eccentricity causes an absolute error of 1 mGal and a relative error of $${10}^{-1}$$ 10 - 1 mGal in gravity measurements and can be corrected by the GNSS antenna array method. (4) Using a GNSS antenna array can obviously improve the measurement accuracy of an instrument with a precision equaling or exceeding 1 mGal, but cannot obviously improve that to an instrument with poor precision (2 mGal or below).

scholarly journals A Review of Antenna Array Technologies for Point-to-Point and Point-to-Multipoint Wireless Communications at Millimeter-Wave Frequencies

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
G. Federico ◽  
D. Caratelli ◽  
G. Theis ◽  
A. B. Smolders
Keyword(s):  
Wireless Communications ◽  
Antenna Array ◽  
Antenna Arrays ◽  
Communication Systems ◽  
High Gain ◽  
Multimedia Services ◽  
Ongoing Research ◽  
Array Technology ◽  
Point To Point ◽  
Technical Solutions

With the introduction of 5G communication systems operating in the mm-wave frequency range, new opportunities in terms of multimedia services and applications will become available. For this to happen, several technical challenges from an antenna standpoint need to be addressed. The achievements of high-gain characteristics and agile beamforming with wide-scan capabilities are the main targets of the ongoing research on mm-wave antenna arrays. In this paper, an up-to-date overview of antenna array technology for wireless communications at mm-wave frequencies is given. Particular focus is put on the review of the state-of-the art and most advanced antenna array concepts for point-to-point and point-to-multipoint radio links at said frequencies. Various figures of merit are assessed for a comprehensive analysis and bench marking of the technical solutions investigated in the presented survey.

scholarly journals ULTRA-WIDEBAND SCANNING ANTENNA ARRAY WIRE EMITTERS

Doklady BGUIR ◽  
2019 ◽  
pp. 5-12
Author(s):  
O. A. Yurtsev ◽  
A. A. Popov
Keyword(s):  
Antenna Array ◽  
Frequency Band ◽  
Antenna Arrays ◽  
Ultra Wideband ◽  
Linear Lattice ◽  
Matching Criterion ◽  
Single Emitter ◽  
Phase Scan ◽  
Overlap Coefficient ◽  
Scanning Antenna

The aim of the work is to determine the properties of the ultra-wideband scanning antenna array of wire emitters. A single element of the grid is a three-dimensional antenna Vivaldi. Numerical simulation of antenna arrays and single Vivaldi emitters was carried out by the method of integral equations in the thin-wire approximation using the original program and the MMANA program. The dimensions of all elements of a single emitter are determined by the criterion of matching and the shape of the radiation pattern for operation in the frequency range 2–18 GHz. The described variant of the antenna according to the matching criterion (SWR < 2) has a frequency overlap coefficient of 12. The narrowing of the frequency band of a single emitter in the composition of non-scanning and scanning gratings within the angle of 30 degrees is determined. The article deals with the range properties of antenna arrays depending on the parameters of the emitters and the possibility of phase scanning. It is shown that the greatest frequency band in agreement has a lattice with a minimum step of placement of emitters. In a flat antenna array, when scanning in the H-plane, the frequency band according to the matching criterion decreases by 2–3 times. It is shown that the linear lattice without scanning has a frequency overlap coefficient equal to 6 according to the criterion of matching emitters. This ratio decreases as the phase scan sector increases. In a flat lattice, the frequency overlap coefficient and the phase scan sector are smaller than in a linear lattice and decrease with the number of rows. The reduced antenna array has a number of design advantages and can be used in systems with ultra-wideband signals.

Design and implementation of artificial magnetic conductor surface as decoupling structure in microstrip antenna arrays

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Khader Zelani Shaik ◽  
Siddaiah P. ◽  
K. Satya Prasad
Keyword(s):  
Antenna Array ◽  
Millimeter Wave ◽  
Antenna Arrays ◽  
Mutual Coupling ◽  
Return Loss ◽  
Wave Spectrum ◽  
Magnetic Conductor ◽  
Content Type ◽  
Artificial Magnetic Conductor ◽  
S Parameters

Purpose Millimeter wave spectrum represents new opportunities to add capacity and faster speeds for next-generation services as fifth generation (5G) applications. In its Spectrum Frontiers proceeding, the Federal Communications Commision decided to focus on spectrum bands where the most spectrums are potentially available. A low profile antenna array with new decoupling structure is proposed and expected to resonate at higher frequency bands, i.e. millimeter wave frequencies, which are suitable for 5G applications. Design/methodology/approach The presented antenna contains artificial magnetic conductor (AMC) surface as decoupling structure. The proposed antenna array with novel AMC surface is operating at 29.1GHz and proven to be decoupling structure and capable of enhancing the isolation by reducing mutual coupling as 8.7dB between the array elements. It is evident that, and overall gain is improved as 10.1% by incorporating 1x2 Array with AMC Method. Mutual coupling between the elements of 1 × 2 antenna array is decreased by 39.12%. Findings The proposed structure is designed and simulated using HFSS software and the results are obtained in terms of return loss, gain, voltage standing wave ratio (VSWR) and mutual coupling. The S-Parameters of each stage of design is tabulated and compared with each other to prove the decoupling capability of AMC surface in antenna arrays. Originality/value The proposed structure is designed and simulated using HFSS software, and the results are obtained in terms of return loss, gain, VSWR and mutual coupling. The S-Parameters of each stage of design is tabulated and compared with each other to prove the decoupling capability of AMC surface in antenna arrays.

BANDWIDTH ENHANCEMENT OF VIVALDI ANTENNA USING TRIANGULAR SHAPED SLOTS

2016 ◽  
Vol 78 (6-3) ◽  
Author(s):  
Wan Nur Aqilah Wan Ahmad Khairuddin ◽  
Mohd Azlishah Othman ◽  
Muhammad Syafiq Noor Azizi ◽  
Mazri Yaakob ◽  
Mohamad Hafize Ramli
Keyword(s):  
Computer Simulation ◽  
Resonant Frequency ◽  
Return Loss ◽  
High Gain ◽  
Simulation Software ◽  
Simulation Technology ◽  
Wide Bandwidth ◽  
Bandwidth Enhancement ◽  
Measurement Result ◽  
Vivaldi Antenna

This paper discusses about a bandwidth enhancement of Vivaldi antenna loaded using triangular shaped. Firstly, a normal Vivaldi antenna using FR-4 substrate had been designed. Then, the triangular shaped slots had been added at the upper layer of the antenna. It shows the better improvement in return loss, gain, directivity and bandwidth operated at frequency of 10 GHz after the addition of the triangular shaped slot. The advantages of a Vivaldi antenna such as simplicity, wide bandwidth, and high gain at microwave.The return loss of this Vivladiantenna with triangular slot is – 18.495 dB at resonant frequency of 10 GHz while for Vivaldi antenna is - 17.818 dB at 10 GHz for measurement result. This proposed antenna had been designed and simulated using Computer Simulation Technology (CST) simulation software.

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