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In this study, a transversal cut of a revolution surface body is inspired to obtain a planarised ultra-wideband antenna. The revolution surface body is based on an inclined conical form to obtain a directive radiation pattern and a triangular reflector to increase the directivity. Once the optimal inclined angle is obtained, the three-dimensional body is segmented obtaining a triangular cut, and the planarised radiator is optimised in order to improve the matching over the required bandwidth. To achieve so, the edges of the radiator are convex-shaped and the resulting antenna performs from 2.8 to 13.1 GHz, for an S11 parameter below -10 dB. The antenna has a directive radiation pattern and an average gain of 7 dB over the entire bandwidth. [ABSTRACT FROM AUTHOR]

In this paper, a novel technique for reducing the dimensions of patch antennas and their arrays is presented. The procedure uses complementary split ring resonators (CSRRs) for increasing the slow-wave effect on the radiator, and therefore augmenting its electrical length, which implicates the modified antenna gets a lower physical dimension than a conventional one for a given frequency. Led by the use of CSRRs, the patches may be closer to each other, without affecting the side lobes magnitude either the directivity of the array compared to a conventional one. As an example, a 4 × 1 patch array was designed and its total area was 40% smaller compared to a conventional one, considering the same design conditions with and without CSRRs. The gain, directivity, and coupling of the prototype were not affected. [ABSTRACT FROM PUBLISHER]

ABSTRACT In this article, a combination of an elliptical UWB monopole with a series of Sierpinski triangle iterations inscribed in the planarized radiator is used to develop a highly-impedance stability UWB antenna, performing from 700 MHz to 9 GHz. The fractal iteration is introduced in order to obtain a radiator size reduction and to improve the current distribution stability. With this implementation, a 31% radiator area reduction is obtained compared to a conventional circular or elliptical radiator. The antenna impedance matching is maintained over the entire bandwidth, even when an external lossy dielectric body is around or even in contact to the radiator. The antenna presents quasi-omnidirectional radiation patterns and a gain around 0 dBi and group delay variations lower than 2 ns, making it suitable for short-pulse communications systems and on-body communications applications. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:635-641, 2017 [ABSTRACT FROM AUTHOR]

ABSTRACT A slot omnidirectional wide-band antenna without stub tuning is proposed. The antenna is fed with a slot waveguide, performing from 1.9 to 6.6 GHz and gain from 2 to 5 dB over the bandwidth. One of the main advantages is the small amount of parameters of the structure to modify and optimize, reducing the design complexity. The idea emerges from a complement of an UWB planarized elliptical monopole. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2658-2662, 2015 [ABSTRACT FROM AUTHOR]

In this article, a novel multiband–multislot planar antenna is presented. The proposed antenna is based on the small loop- and slot radiators, showing multiple resonances. The antenna is built on a substrate with a permittivity of 2.2 and a thickness of 1.27 mm. The antenna resonates at 0.84, 1.55, 2.5 and 4.8 GHz behaving with quasi-omnidirectional radiation patterns, which can be employed in the state of the art automotive technology, laptops and tablets among other terminal devices. The resonances can be shifted to lower or higher frequencies depending on the slots’ length and width, as well as the magnetic coupling among them. Moreover, additional resonances can be introduced by etching new slots on the substrate metallization. [ABSTRACT FROM AUTHOR]

In this work, an ultra-wideband planar inverted-F antenna is presented, fed by a convex-shaped structure. The antenna shows a measured ultra-wide bandwidth starting at 2.7 GHz and ending at 13 GHz, for a VSWR less than 2. The antenna shows an omnidirectional pattern at the X–Y plane with a very low out-of-roundness all over the bandwidth. The group delay of the antenna is very stable, obtaining a variation less than 1 ns. As a result, very low dispersion over the entire bandwidth is presented, as well as low cross-polarization level. [ABSTRACT FROM PUBLISHER]

A reduced-size four-port antenna array with highly electromagnetic isolation based on a metamaterial structure is presented. The radiator antenna unit is created using the split ring resonator (SRR) arrangement, which has been widely demonstrated to perform as metamaterial. The metamaterial comportment allows increasing the slow-wave factor on the structure, and as a result, the array size is 42 × 42 mm 2 , where each radiator presents a 52% length reduction compared to a conventional disc monopole with lower cutoff frequency of 2.5 GHz. The separation among elements is very small, achieving values of 0. 045 λ at the resonance; however, despite the proximity among elements, the electromagnetic isolation reaches values around 30 dB all over the working band. The antenna has a wide bandwidth, going from 2.5 GHz to almost 4 GHz. The array performs a very low Envelope Correlation Coefficient (ECC), achieving levels lower than 0.035 and a steady Total Active Reflection Coefficient (TARC), obtaining a system bandwidth of 1.38 GHz for a TARC ≤ − 10 dB , resulting a suitable structure for Multiple-Input Multiple-Output (MIMO) applications. [ABSTRACT FROM AUTHOR]

In this work, two techniques are introduced in order to reduce the dimensions of strip antennas. As an example, reduced size dipoles with no efficiency degradation are accomplished by introducing a stub load and a defected microstrip structure. For a specific configuration, a dual frequency operation can be achieved obtaining the same gain compared to a conventional strip dipole. Moreover, this technique gives the opportunity to get the same bandwidth for certain stub dimensions. Combining both techniques, the efficiency of the antenna and the cross-polarization ratio are kept with an antenna length reduction of 33%. [ABSTRACT FROM AUTHOR]

ABSTRACT In this work, a reduced size planarized antenna based on metamaterial split-ring resonators (SRRs), for personal communications, is presented. The antenna is based on different size concentric SRRs that operates in the R band, centered at 2.3 GHz. The antenna area is about 15 × 25 mm2, approximately. The measured antenna gain is around −3 dB, with an omnidirectional pattern, and the measured bandwidth is about 1 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2345-2350, 2013 [ABSTRACT FROM AUTHOR]

A new technique is employed to reduce the size of Yagi-Uda antennas. The technique consists of adding short circuited cylindrical covers to the structure, making the elements be inductively loaded, and as a result, increase the electric length. A prototype resonating at 660 MHz is developed, and compared to a conventional Yagi-Uda antenna. An effective area reduction of 35% is achieved without decreasing, considerably, the gain, preserving the bandwidth, and front to back lobe ratio. [ABSTRACT FROM AUTHOR]

In this article, a combination of rectangular loop array and slot radiator for multiband applications is presented. The antenna is configured by arranging, concentrically, a set of rectangular loop radiators excited by electromagnetic coupling provided by a dumbbell slot. The size of the loops is calculated to obtain the desired resonant frequencies, which are almost independent of the adjacent rings. The exciting slot is designed to operate in a wideband frequency range to cover the upper desired resonance. In addition, to obtain directive radiation patterns, a reflector shaped like a box is introduced, giving a stable gain, radiation pattern shape, and port matching at the selected frequencies. The configuration presents great results, since to the authors' knowledge, even a similar configuration given in the open literature presents some disadvantages compared to this one; moreover, not just any structure can be employed as the resonating elements, obtaining multiband behavior at the same time. [ABSTRACT FROM AUTHOR]

Three simple methods to improve the third-order intercept point (IP3) of a low-noise amplifier (LNA) for personal communication systems (PCS) applications or CDMA cellular handsets are introduced. Both simulations and results from previous works in the literature are compared in order to demonstrate the effectiveness of these methods in improving the performance of the LNA in terms of linearity when low-bias voltage is used. The LNA was designed to operate at 1.9 GHz, using a silicon germanium (SiGe) heterojunction bipolar transistor (HBT) and 2.4 V bias voltage. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 308–311, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10903 [ABSTRACT FROM AUTHOR]