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Design of Frequency Selective Surface (FSS) Printed Antennas
Published in Binod Kumar Kanaujia, Surendra Kumar Gupta, Jugul Kishor, Deepak Gangwar, Printed Antennas, 2020
Kanishka Katoch, Naveen Jaglan, Samir Dev Gupta, Binod Kumar Kanaujia
One of the most desired features in microwave and optical range signal processing systems is spatial filtering. Frequency selective surface (FSS) is also a type of spatial filter, which offer transmission and reflection characteristics by modifying the electromagnetic incident wave striking its surface. FSS are two-dimensional planar structures arranged in a periodic manner. Metallic arrays (apertures or patch), as shown in Figure 12.1, are etched over a dielectric substrate, exhibiting partial or full transmission or reflection of the incident wave at a particular frequency [1]. The amplitude and phase of the transmitted wave vary after striking the FSS when compared to the incident wave. This occurs when the resonance frequency of the FSS matches the plane wave frequency. Therefore, in free space, FSS can either block or pass the incident wave at a particular frequency.
F
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
frequency reuse cluster directions of the other beams or polarization (and vice versa) is low enough. Isolations of 27-35 dB are typical for reuse systems. frequency reuse cluster a group of cells in a cellular communications network wherein each frequency channel allocated to the network is used precisely once (i.e., in one cell of the group). The size of the frequency reuse cluster is one of the major factors that determines the spectral efficiency and ultimately the capacity of a cellular network. For a given channel bandwidth, the smaller the cluster size, the higher the network capacity. frequency selective filter a filter that passes signals undistorted in one or a set of frequency bands and attenuate or totally eliminate signals in the remaining frequency bands. frequency selective surface (FSS) filter made of two-dimensional periodic arrays of apertures or metallic patches of various shapes. Several layers can be used to obtain a structure with a set of desired spectral properties. frequency shift keying (FSK) (1) an encoding method where different bits of information are represented by various frequencies; used for spread-spectrum signal encoding for security and reduced interchannel interference. (2) a digital modulation technique in which each group of successive source bits determines the frequency of a transmitted sinusoid. frequency space the transformed space of the Fourier transform. frequency synchronization the process of adjusting the frequency of one source so that it exactly matches that of another source: more specifically, so that n periods of one frequency are exactly equal to m periods of the other frequency, for integral n and m. See phase-locked loop. frequency synthesizer an oscillator that produces sinusoidal wave with arbitrary frequency. In common cases, generated frequencies are allocated with a frequency spacing called the channel step. frequency variation supply frequency. a change in the electric
Tunable Surfaces: Modeling and Realizations
Published in Filippo Capolino, Theory and Phenomena of Metamaterials, 2017
Chinthana Panagamuwa, J. (Yiannis) C. Vardaxoglou
With advances in electronics and the continuous creation of new applications, tunable surfaces have become a reality. At first, tunable frequency-selective surfaces (FSS) provided a method for dynamically controlling the transmission and reflection characteristics of an incident wave. It became possible to reduce the size of the unit cell, improve the bandwidth, and shift the operating frequency in real-time.
Terahertz reconfigurable multi-functional metamaterials based on 3D printed mortise-tenon structures
Published in Virtual and Physical Prototyping, 2023
Bo Yu, Lesiqi Yin, Peng Wang, Cheng Gong
Thirdly, the Frequency Selective Surface (FSS) theory plays an important role in the narrowband peak of transmission in structure A or reflection in structure A + C. FSS is a kind of two-dimensional periodic array structure, which is essentially a spatial filter, which is widely used from microwave to visible bands due to its specific frequency selective effect. In the metamaterials with mortise and tenon structure, cross gap and cross metal could be considered as the FSS. The lower-layer cross gap of structure A could act as the FSS to selectively leak the terahertz wave at 0.14THz, while the metal cross of structure A + C could act as the FSS to selectively reflect the terahertz wave at 0.10THz. In summary, we analyze the working mechanism of the multi-band metamaterials through a theoretical model based on impedance matching, Debye relaxation, and FSS theory, where the dielectric loss and Mie resonances realise broadband absorption and the FSS realises narrowband transmission and reflection. The above functions are realised by the combination of various stereo cross structures (cross dielectric, cross gap & cross metal), and they are switched by mortise and tenon structure combination.
Wearable metamaterial for electromagnetic radiation shielding
Published in The Journal of The Textile Institute, 2022
Oriol Almirall, Raul Fernández-García, Ignacio Gil
A frequency-selective surface (FSS) is a structure consisting most typically of two-dimensional periodic elements, where an array of conducting patches act as a bandstop filter, namely, rejecting waves at the patches resonant frequency but passing them at higher and lower frequencies (Te-Kao, 2005), as depicted schematically in Figure 2. The appropriate selection of FSSs array elements, shape, dimensions and substrate materials are the most important parameters in the design process (Anwar et al., 2018), since these are the parameters that will define both the properties of the surface and the resonance frequency (fr), which is a result of the impedance and the conductance of the surface (Munk, 2000). One possible combination for doing this is by using conductive textiles, which are usually made from polymer metal coated yarns, and a nonconductive fabric as a substrate. Since conductive yarns are prone to damage by bending and stretching, it is difficult to manufacture a homogeneous conducting prototype by embroidering with them. This fact, along with the embroidering technique, has to be considered in order to predict the electric performance of wearable metamaterials (Alonso González, 2018).
Triple Band-stop Performance Realization Through a Single Substrate Layer Frequency Selective Surface
Published in IETE Journal of Research, 2022
V. Nadjari, J. Nourinia, Ch. Ghobadi
Periodic structures that encounter electromagnetic waves and act as filters, but are a function of frequency, called Frequency Selective Surfaces(FSS). FSSs are filters that result from the placement of several identical metal shapes together in a repetitive pattern printed on a substrate. According to their design, they can reject or pass electromagnetic waves radiated toward them. These electromagnetic filters can act as band-stop, band-pass, low-pass, and high-pass filters like microwave filters [1–3]. Perhaps the biggest problem of a periodic structure is that it conceptually is so simple that almost everyone understands it instantly. However, the designer soon realizes that one has to produce more than just some calculated curves [4]. FSSs have many advantages; however, there are some difficulties in designing and manufacturing them that need to be considered. These difficulties include the following [5]: Large-size unit cells, the larger the cell, the larger the FSS;Difficulties in achieving the desired band and specific frequency range;Complex structures, which make FSS challenging to build;The number of substrate layers.