In this paper, a dual-band frequency selective rasorber(FSR) is proposed based on a composite absorption structure. The FSR is a three-tier structure composed of lossy layer I, lossy layer II and a dual-band frequency selective surface (FSS). The lossy layer I is composed of a lossy cross-shaped structure in which, dual-passband resonators are added and constructed by parallel interdigital capacitors and meandering strip inductors(PLC). The lossy layer II is composed of a hybrid circular strip resonator loaded with lossy elements. FSS is implemented in two Jerusalem slots. By combining the lossy layers I and II as a composite lossy structure, the absorption bands of lossy layers I and II are successfully connected in the frequency response, and the bandwidth of S ₁₁ under -10dB is extended from 3.1 to 20.6GHz. The proposed FSR integrate dual-band, dual-polarized, and broadband absorption performance simultaneously. Finally, a prototype of the composite FSR is fabricated to validate the simulated results.

A low-profile, wideband, and high-gain antenna array, based on a novel double-H-shaped slot microstrip patch radiating element and robust against high temperature variations, is proposed in this work. The antenna element was designed to operate in the frequency range between 12 GHz and 18.25 GHz, with a 41.3% fractional bandwidth (FBW) and an obtained peak gain equal to 10.2 dBi. The planar array, characterized by a feed network with a flexible 1 to 16 power divider, comprised 4 × 4 antenna elements and generated a pattern with a peak gain of 19.1 dBi at 15.5 GHz. An antenna array prototype was fabricated, and the measurements showed good agreement with the numerical simulations as the manufactured antenna operated in the range of 11.4–17 GHz, with a 39.4% FBW, and the peak gain at 15.5 GHz was 18.7 dBi. The high-temperature simulated and experimental results, performed in a temperature chamber, demonstrated that the array performance was stable in a wide temperature range, from −50 °C to 150 °C.

In this paper, two new methods are proposed for miniaturizing planar ultra-wideband horizontally-polarized omnidirectional Vivaldi antenna arrays. In the first method, the order of a power divider is decreased by means of feeding two neighboring Vivaldi antenna elements in series as a sub-array, or termed as a double-Vivaldi antenna element and thus the layout area required for a feeding network is reduced. Therefore, the layout problem of a conventional circular Vivaldi antenna array with a confined size is solved. Meanwhile, non-uniform elements with different taper rates are used to solve the in-band peak gain variation that is caused by a disc monopole mode. In this way, a non-uniform series-fed double-Vivaldi antenna array is presented. In the second method, a folded loop structure is introduced for an electrical size reduction of the aforementioned array. As a result, a lower resonant frequency is obtained. Measured results show that the final design has advantages of a large operating bandwidth, a small footprint of π × (0.284λ _max ) ² and a high gain. Besides, a clear design flowchart is given.

A compact third-order filtering antenna array with high gain and two controllable radiation nulls is proposed. The antenna consists of one narrow patch in the center fed by the coaxial port and four wide patches placed around it. Four short-end stub-loaded resonators are capacitively coupled between the center patch and the outer patches, which makes the radiated E-fields of the center patch and the outer patches in-phase at the center frequency of the passband to realize the high gain and out-of-phase at the low and high stopbands to introduce a pair of radiation nulls. The working principle of the filtering antenna array can be explained by the coupled-resonator network. Finally, a filtering antenna array centered at 3.5 GHz with a fractional bandwidth of 4.26%, a high maximum gain of 12.2 dBi, high out-of-band selectivity, and wide stopband is designed, fabricated, and measured.

In this study, a novel interval analysis (IA) approach for linear arrays with element pattern tolerance is proposed. This study differentiates itself from the classic interval analysis (CIA) method because it focuses on the effects of the array element (e.g., patch) pattern tolerance on the antenna array pattern; the tolerance may be caused by fabrication errors in the element. The closed-form pattern expressions of the element (e.g., patch) and array are deduced by the interval arithmetic method. To mitigate the interval extension (also referred to as the overestimation problem) caused by the dependency problem, Taylor expansion and matrix-based interval analysis (TMIA) methods are proposed and implemented in this study. A set of numerical examples is reported and analyzed to indicate the effectiveness of the proposed TMIA approach with the results of Monte Carlo (MC) and CIA methods, as well as to indicate its potential capabilities and advantages in the actual application of industrial antenna arrays.

An ultra-wide pass-band and dual-polarized frequency selective surface for K-Ka frequency band is presented. The characteristics of wide passband, angular stability, and fast roll-offs are realized by using LC resonant structures and multi-layer coupling. The whole structure of the frequency selective surface cell is symmetrical, realizing TE and TM polarization. A prototype of the proposed FSS is manufactured and measured. The size of the prototype is 123.6 mm×123.6 mm×2.961 mm. The measured results have a good agreement with the simulated ones. The measured passband is from 18.3GHz to 37.2 GHz (K-Ka frequency band), of which the relative bandwidth is 68.1%. Moreover, the passband has little change within the incidence angle ±40° for both TE and TM polarization. Therefore, the FSS can be widely used in the communication system.