scholarly journals A DRESSED-STATE ASSISTED LEFT-HANDED COHERENT MEDIUM FOR HIGH-GAIN OPTICAL AMPLIFICATION

2013 ◽  
Vol 143 ◽  
pp. 263-284
Author(s):  
Jian-Qi Shen
Keyword(s):  
High Gain ◽  
Optical Amplification ◽  
Left Handed ◽  
Dressed State

scholarly journals High-Efficiency Polarizer Reflectarray Antennas for Data Transmission Links from a CubeSat

Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1802
Author(s):  
Eduardo Martinez-de-Rioja ◽  
Daniel Martinez-de-Rioja ◽  
Rafael López-Sáez ◽  
Ignacio Linares ◽  
Jose A. Encinar
Keyword(s):  
Circular Polarization ◽  
Data Transmission ◽  
High Efficiency ◽  
High Gain ◽  
Dual Band ◽  
Left Handed ◽  
Linearly Polarized ◽  
Flat Profile ◽  
First Time ◽  
Collimated Beam

This paper presents two designs of high-efficiency polarizer reflectarray antennas able to generate a collimated beam in dual-circular polarization using a linearly polarized feed, with application to high-gain antennas for data transmission links from a Cubesat. First, an 18 cm × 18 cm polarizer reflectarray operating in the 17.2–22.7 GHz band has been designed, fabricated, and tested. The measurements of the prototype show an aperture efficiency of 52.7% for right-handed circular polarization (RHCP) and 57.3% for left-handed circular polarization (LHCP), both values higher than those previously reported in related works. Then, a dual-band polarizer reflectarray is presented for the first time, which operates in dual-CP in the frequency bands of 20 GHz and 30 GHz. The proposed antenna technology enables a reduction of the complexity and cost of the feed chain to operate in dual-CP, as a linear-to-circular polarizer is no longer required. This property, combined with the lightweight, flat profile and low fabrication cost of printed reflectarrays, makes the proposed antennas good candidates for Cubesat applications.

scholarly journals Composite right/left‐handed based compact and high gain leaky‐wave antenna using complementary spiral resonator on HMSIW for Ku band applications

2018 ◽  
Vol 12 (8) ◽  
pp. 1310-1315 ◽  
Author(s):  
Anirban Sarkar ◽  
Moitreya Adhikary ◽  
Abhishek Sharma ◽  
Animesh Biswas ◽  
Mohammed Jaleel Akhtar ◽  
...  
Keyword(s):  
High Gain ◽  
Leaky Wave ◽  
Left Handed ◽  
Leaky Wave Antenna ◽  
Wave Antenna ◽  
Ku Band

Circularly polarized microstrip antenna arrays with reduced mutual coupling using metamaterial

2015 ◽  
Vol 8 (8) ◽  
pp. 1253-1263 ◽  
Author(s):  
R. Hafezifard ◽  
Jalil Rashed-Mohassel ◽  
Mohammad Naser-Moghadasi ◽  
R. A. Sadeghzadeh
Keyword(s):  
Antenna Arrays ◽  
Microstrip Antenna ◽  
Mutual Coupling ◽  
Ground Plane ◽  
High Gain ◽  
Ring Resonators ◽  
Magnetic Characteristics ◽  
Circularly Polarized ◽  
Antenna Performance ◽  
Left Handed

A circularly polarized (CP) and high gain Microstrip antenna is designed in this paper using metamaterial concepts. The antenna, built on a metamaterial substrate, showed significant size reduction and less mutual coupling in an array compared with similar arrays on conventional substrates. Demonstrated to have left-handed magnetic characteristics, the methodology uses complementary split-ring resonators (SRRs) placed horizontally between the patch and the ground plane. In order to reduce mutual coupling in the array structure, hexagonal-SRRs are embedded between antenna elements. The procedure is shown to have great impact on the antenna performance specifically its bandwidth which is broadened from 400 MHz to 1.2 GHz for X-band and as well as its efficiency. The structure has also low loss and improved standing wave ratio and less mutual coupling. The results show that a reduction of 26.6 dB in mutual coupling is obtained between elements at the operation frequency of the array. Experimental data show a reasonably good agreement between simulation and measured results.

AN INVESTIGATION OF MULTI-FUNCTIONAL SEMICONDUCTOR BISTABLE LASER

1996 ◽  
Vol 07 (03) ◽  
pp. 383-397
Author(s):  
QIMING WANG ◽  
RONGHAN WU ◽  
SHIMING LIN ◽  
JIANMENG LI ◽  
FEIKE XIONG ◽  
...  
Keyword(s):  
High Speed ◽  
Mode Conversion ◽  
Relaxation Oscillation ◽  
Optical Memory ◽  
Longitudinal Mode ◽  
High Gain ◽  
Pulse Generation ◽  
Optical Amplification ◽  
Signal Light ◽  
Bistable Switching

The co-cavity two-section (CCTS) bistable semiconductor laser with DH and MQW structures has been investigated experimentally and theoretically in this laboratory. Many attractive functions, such as optical bistable switching, optical memory effect, high stability of single longitudinal mode emission spectrum in steady on state, high gain optical amplification, mode conversion effect on injecting signal light, long delay and abnormal relaxation oscillation, ultrafast light pulse generation are investigated in the device. As a high speed, single wavelength, novel laser light source, a monolithic MQW CCTS bistable laser with MQW EA modulator has been fabricated.

High-gain optical amplification in Eu^3+-doped polymer

2010 ◽  
Vol 35 (4) ◽  
pp. 520 ◽  
Author(s):  
Kwok Chu Tsang ◽  
Chun-Yuen Wong ◽  
Edwin Yue Bun Pun
Keyword(s):  
High Gain ◽  
Optical Amplification ◽  
Doped Polymer

scholarly journals Compact and High Gain 4 × 4 Circularly Polarized Microstrip Patch Antenna Array for Next Generation Small Satellite

2021 ◽  
Vol 11 (19) ◽  
pp. 8869
Author(s):  
Manzoor Elahi ◽  
Son Trinh-Van ◽  
Youngoo Yang ◽  
Kang-Yoon Lee ◽  
Keum-Cheol Hwang
Keyword(s):  
Antenna Array ◽  
Patch Antenna ◽  
Axial Ratio ◽  
High Gain ◽  
Microstrip Patch Antenna ◽  
Small Satellite ◽  
Next Generation ◽  
Circularly Polarized ◽  
Microstrip Patch ◽  
Left Handed

In this article, a high gain and compact 4 × 4 circularly polarized microstrip patch antenna array is reported for the data transmission of the next-generation small satellite. The radiating element of the circularly polarized antenna array is realized by the conventional model of the patch with truncated corners. A compact two-stage sequential rotational phase feeding is adopted that broadens the operating bandwidth of the 4 × 4 array. A small stub is embedded in the sequential rotational feed, which results in better performance in terms of the S-parameters and sequential phases at the output ports than sequential rotational feed without open stub. A prototype of the array is fabricated and measured. Fulfilling the application requirements of the next-generation small satellites, the array has the left-handed circularly polarized gain of more than 12 dBic with the axial ratio level below 1.5 dB in the ±10∘ angular space with respect to the broadside direction for the whole bandwidth from 8.05 GHz to 8.25 GHz. Moreover, the left-handed circularly polarized gain varies from 15 to 15.5 dBic in the desired band. The radiation patterns are measured; both the co- and X-pol are validated.

scholarly journals Right/Left-Handed Leaky Rectangular Waveguide with Broadside Radiation Property

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Xingying Huo ◽  
Zheng Li
Keyword(s):  
Radio Wave ◽  
Rectangular Waveguide ◽  
High Gain ◽  
Shadow Region ◽  
Confined Spaces ◽  
Left Handed ◽  
Half Power ◽  
The Right ◽  
Broadside Radiation ◽  
Leaky Waveguide

When a leaky rectangular waveguide is used to realize the coverage of radio wave in the small confined spaces, there will be a shadow region, which influences the coverage performance. In this paper, the traditional leaky rectangular waveguide is improved according to the principle of the equivalent circuit, by cutting interdigital slots in the upper wall and adding uniserial metal vias between the upper and lower walls of the rectangular waveguide. Thus, the right/left-handed transmission line property is introduced to the periodic leaky-waveguide (LWG), realizing the broadside radiation with relatively high gain (15.7 dBi), good cross polarization (−50 dB), and narrow half-power beamwidth (10.9°) at 6.97 GHz and providing a method for a uniform coverage of the radio wave in rooms without a shadow region.

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