Effect of Internal Resonance on the Radar Cross Section and Shield Effectiveness of Open Spherical Enclosures

Hussein, Khalid F. A.

doi:10.2528/pier07012101

Cited by 18 publications

(16 citation statements)

References 12 publications

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“…This design necessitates that the CPWR has the same cross section as that of the CPWTL, i.e., the strips and slots of the CPWR have the same width as those of the CPWTL. As long as the operating frequency is far from the resonant frequencies of the U-shaped CPWR, the CPWTL is almost unloaded leading to complete microwave power transfer between the filter ports (1) and (2). Only over very narrow frequency band around the resonant frequency, the microwave power is absorbed and stored in the U-shaped CPWR preventing any power transfer between the filter ports and, thereby, leading to high Q-factor bandstop filter response.…”

Section: The Proposed Bandstop Filter Designmentioning

confidence: 99%

“…Microwave fields in three-dimensional [1,2], two-dimensional (printed patches or etched slots), and quasi-one dimensional cavities (printed transmission lines) [3,4] are known to exhibit very sharp peaks over very narrow frequency intervals leading to very high Q-factor resonators. Such resonators can be used to design high Q-factor bandpass and bandstop filters.…”

Section: Introductionmentioning

confidence: 99%

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High Q-Factor Bandstop Filter Based on CPW Resonator Broadside-Coupled to CPW Through-Line

Fahmy¹,

Farahat²,

Hussein³

et al. 2020

PIER B

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High Q-factor bandstop filter based on broadside-coupling between U-shaped coplanar waveguide (CPW) resonator and CPW through-line (CPWTL) is proposed in the present paper. The CPWTL is printed on the top layer of the dielectric substrate whereas the CPW resonator (CPWR) is printed on the bottom layer. Only over very narrow frequency band around the resonant frequency of the CPWR the microwave power flowing in the CPWTL is coupled to (absorbed by) the CPWR leading to a bandstop filter of very high Q-factor. A CPWR with side ground strips of finite width is shown to have much higher Q-factor than that of infinitely extending side ground planes. Owing to the lower profile of the CPW with finite-width, the radiation loss is reduced, and the structure has narrower frequency band for coupling, which results in much higher Q-factor than other published works. The dimensions of the CPWTL are optimized for impedance matching whereas the dimensions of the Ushaped CPWR are optimized to obtain the highest possible Q-factor. The effect of the loss tangent of the dielectric substrate material on the Q-factor is investigated. A prototype of the proposed filter is fabricated and experimentally studied for more understanding of the underlying physical principles of operation and for experimental investigation of the filter performance. The experimental measurements show good agreement with the corresponding simulation results.

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Section: The Proposed Bandstop Filter Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High Q-Factor Bandstop Filter Based on CPW Resonator Broadside-Coupled to CPW Through-Line

Fahmy¹,

Farahat²,

Hussein³

et al. 2020

PIER B

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“…and the RCS can be calculated as [13], RCS = backscattered power in the direction of the radar power density of the incident plane wave = 4πr…”

Section: Application Of the Efie Technique And Calculation Of The Scamentioning

confidence: 99%

Spatial Filters for Linearly Polarized Antennas Using Free Standing Frequency Selective Surface

Farahat¹,

Hussein²,

El-Minyawi³

2008

PIER M

Self Cite

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Abstract-Free standing planar frequency selective surfaces (FSSs) are studied when utilized as spatial filters for linearly polarized antennas. The antenna spatial filter investigated in the present work is constructed up as a finite planar array of conducting strip dipoles. The electric field integral equation (EFIE) technique with the Rao-WiltonGlison (RWG) basis functions are used to get the current distribution on the conducting strips. The current distribution and backscattered electric field due to an incident plane wave are calculated and compared to some published work. The effect of polarization on the scattered field, and the frequency response of the spatial filter are studied. To test the operation of the proposed planar FSS, a bowtie antenna is used with the FSS employed as a spatial filter. The field transmitted by the antenna and passed over a wide frequency band through the FSS is calculated. It is shown that such a free standing planar FSS can operate as a band stop filter for linearly polarized antennas. It is also shown that even when the size of the array is reduced, the FSS maintains its frequency response with a very slight change in the center frequency of the stop band. The effect of element size, spacing between the elements, and interleaving the columns of the FSS on the frequency response of the FSS are studied. The effect of the spatial filter on the antenna input impedance is studied over a wide frequency band. The radiation pattern of the bowtie is calculated in the presence 168 Farahat, Hussein, and El-Minyawi of the spatial filter. It is shown that the existence of the later causes considerable reduction in the radiation pattern within the stop band of the filter.

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“…The CFIE technique requires the calculation of both and impedance matrices and it is not suitable for aperture problems. The combined source integral equation (CSIE) [8,9] technique makes up for aperture structures. Also a technique has been proposed by Mittra and Klein [10], involving application of the generalized boundary condition [11], and consists of additional points in the interior of the conductor and forces the field to be zero at those points.…”

Section: Introductionmentioning

confidence: 99%

An Effective Math Model for Eliminating Interior Resonance Problems of EM Scattering

Zhang

Zhong-shan

Zhi-guo

et al. 2015

International Journal of Microwave Science and Technology

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It is well-known that if an -field integral equation or an -field integral equation is applied alone in analysis of EM scattering from a conducting body, the solution to the equation will be either nonunique or unstable at the vicinity of a certain interior frequency. An effective math model is presented here, providing an easy way to deal with this situation. At the interior resonant frequencies, the surface current density is divided into two parts: an induced surface current caused by the incident field and a resonance surface current associated with the interior resonance mode. In this paper, the presented model, based on electric field integral equation and orthogonal modal theory, is used here to filter out resonant mode; therefore, unique and stable solution will be obtained. The proposed method possesses the merits of clarity in concept and simplicity in computation. A good agreement is achieved between the calculated results and those obtained by other methods in both 2D and 3D EM scattering.

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Effect of Internal Resonance on the Radar Cross Section and Shield Effectiveness of Open Spherical Enclosures

Cited by 18 publications

References 12 publications

High Q-Factor Bandstop Filter Based on CPW Resonator Broadside-Coupled to CPW Through-Line

High Q-Factor Bandstop Filter Based on CPW Resonator Broadside-Coupled to CPW Through-Line

Spatial Filters for Linearly Polarized Antennas Using Free Standing Frequency Selective Surface

An Effective Math Model for Eliminating Interior Resonance Problems of EM Scattering

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