A DUAL-FREQUENCY MATCHING NETWORK FOR FDCLS USING DUAL-BAND λ/4-LINES

2015 ◽  
Vol 52 ◽  
pp. 23-30 ◽  
Author(s):  
Mohammad A. Maktoomi ◽  
Mohammad S. Hashmi ◽  
Vipul Panwar
2021 ◽  
Author(s):  
Jinkai Li ◽  
Xiaoxi Zhang ◽  
Yaoxu Lei ◽  
Huiqing Zhai ◽  
Changyuan Liu

2021 ◽  
Author(s):  
Yijiao Fang ◽  
Jiangwei Zhong

Abstract A novel dual-band conformal surface plasmons (CSPs) waveguide is designed and well studied in this paper. In earlier researches, we have recognized that electromagnetic field of CSPs waveguide are always confined to a sub-wavelength area and have a strong potential to be applied in devices designing. However, almost all of the earlier CSP structures is mainly focus on the fundamental mode characteristics with only single resonance frequency. Here we propose a innovative dual inverted-L structure with excellent performance not only on the fundamental mode but also on a new upper mode. This structure operates in microwave frequencies regime and shows outstanding frequency tunability characteristic. Being different from frequency characteristics in the earlier CSP waveguides which always used to be designed single-frequency device, dual-frequency tunability can be obtained via the dual L-type bending branch of the periodical CSP structure. In present paper, we also realize a tunable dual-frequency filter by changing the scaling factor of inverted-L stubs.


2021 ◽  
Author(s):  
Rosemary Willatt ◽  
Julienne Stroeve ◽  
Vishnu Nandan ◽  
Rasmus Tonboe ◽  
Stefan Hendricks ◽  
...  

<p>Retrieving the thickness of sea ice, and its snow cover, on long time- and length-scales is critical for studying climate. Satellite altimetry has provided estimations of sea ice thickness spanning nearly three decades, and more recently altimetry techniques have provided estimations of snow depth, using dual-band satellite altimetry data. These approaches are based on assumptions about the main scattering surfaces of the radiation. The dominant scattering surface is often assumed to be the snow/ice interface at Ku-band frequencies and the air/snow interface at Ka-band and laser frequencies. It has previously been shown that these assumptions do not always hold, but field data to investigate the dominant scattering surfaces and investigate how these relate to the physical snow and ice characteristics were spatially and temporally limited. The MOSAiC expedition provided a unique opportunity to gather data using a newly-developed Ku- and Ka-band radar 'KuKa' deployed over snow-covered sea ice, along with coincident field measurements of snow and ice properties. We present transect data gathered with the instrument looking at nadir to demonstrate how the scattering characteristics vary spatially and temporally in the Ku- and Ka-bands, and discuss implications for interpretation of dual-frequency satellite radar altimetry data. We compare KuKa data with field measurements to demonstrate snow depth retrieval using Ku- and Ka-band data.</p>


Author(s):  
Sumit Kumar ◽  
Amruta S. Dixit

Abstract This paper presents a dual-band 1 × 4 antipodal Vivaldi antenna (AVA) array with high gain to operate over a dual-frequency band that covers the 5G frequency spectrum. The gain is enhanced by employing a dielectric lens (DL). The AVA array consists of four radiating patch elements, corrugations, DL, and array feeding network on the top side. The bottom side contains four radiating patches which are the mirror images of top radiating patches. The designed AVA contains 1 × 4 array antenna elements with a DL that is operating in the ranges of 24.59–24.98 and 27.06–29 GHz. The dimensions of the designed antenna are 97.2 mm × 71.2 mm × 0.8 mm. For the improvement in gain and impedance matching at the dual-band frequency, corrugation and feeding network techniques are used. The gain obtained is about 8–12 dBi. AVA array is tested after fabrication and the measured results are reliable with the simulation results.


Author(s):  
P. Mukherjee ◽  
E. L. Hines

This chapter focuses on the application of Genetic Algorithms (GAs) techniques in overcoming the limitations of microstrip antennas in terms of several key parameters such as bandwidth, power-handling capacity etc. In this chapter the effectiveness of GAs is discussed in relation to Electromagnetic optimization. A matching network has been designed for single band and dual band matching of microstrip antenna using GA.


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