A small-size multiband antenna with 14 bands is presented in this paper for wireless applications. The studied antenna mainly consists of a folded monopole antenna and an M-shaped structure. Furthermore, the antenna has a simple design with a compact dimension of 26.8 × 10.8 mm2. The studied antenna is printed on FR4 substrate with a depth of 0.8 mm and fed by a coaxial cable. The −10 dB bandwidths measured are 210 MHz (1200–1410 MHz), 100 MHz (2200–2300 MHz), 193 MHz (3000–3193 MHz), 180 MHz (3330–3510 MHz), 390 MHz (4110–4500 MHz), 4971 MHz, 577 MHz (5300–5877 MHz), and 700 MHz (7100–7800 MHz), which can cover 3G/4G/5G/Wi-Fi/WiMAX, C, and S bands. The gain and efficiency of the presented antenna are 1.3–4.00 dBi and 46%–60.2%, respectively.

A rectangular monopole antenna with an extended ground, excited by Coplanar Waveguide (CPW) and backed by a 6 × 6 array of fractal artificial magnetic conductor (AMC) unit cells, resonating at 5.8 GHz in Industrial, Scientific, and Medical (ISM) band, is presented in this manuscript. To attain the objective of proposing a compact and economical antenna solution for employment in wearable biomedical domain, a novel approach of utilizing both surfaces of the same dielectric for engraving antenna element as well as AMC array is adopted. It results in the elimination of layers of expensive substrate (RO3003) and of thick separator (foam) between antenna and AMC array. During measurement in open space, the proposed antenna system exhibited an impedance bandwidth of 570 MHz with a gain of 7.9 dBi. While a total realized gain of 7.5 dBi, amounting to a gain enhancement of about 3 dB as compared to that of monopole alone, is observed when the integrated antenna system is placed just over a three-layer rectangular human body equivalent model. Specific absorption rate values, as calculated at 5.8 GHz and averaged over 1 and 10 g of human tissue, are 0.0117 and 0.00244 W/kg, respectively. Obtained results strongly advocate the use of the proposed antenna system in smart wearable healthcare devices.

A compact antenna module with a single band notch at wireless local area network (WLAN) (5.725–5.825 GHz) for ultra-wideband (UWB) multiple input multiple output (MIMO) applications is proposed. Proposed antenna which acquires size of 0.299 λ × 0.413 λ × 0.005 λ mm3 at 3.1 GHz consists of two symmetrical radiators placed side by side on global merchandise link (GML) 1000 substrate (εr = 3.2, tan δ = 0.004). Isolation between the antenna elements is >18 dB in the whole UWB band, which is achieved by introducing the vertical stub and H-slot between the monopole radiators in the ground plane. The simulated and measured results of the antenna system are in good agreement. The proposed antenna covers entire UWB with impedance bandwidth (|S11| < −15 dB) from 3.1 to 11 GHz except at WLAN notched band. The designed antenna module bears low envelope correlation coefficient and minimal multiplexing efficiency hence fulfilling criteria suitable for various wireless MIMO applications.

A compact ultra-wideband (UWB) monopole antenna with reconfigurable band-notch characteristics is demonstrated in this paper. It is comprised of a modified rectangular patch and a defected ground plane. The band-notch property in the WiMAX and WLAN bands is achieved by etching an open-ended slot on the radiating patch and an inverted U-shaped slot on the ground plane, respectively. To obtain the reconfigurable band-notch performance, two PIN diodes are inserted in the slots, and then the notch-band can be switched by changing the states of the PIN diodes. The antenna has a compact size of 0.47 λ1 × 0.27 λ1. The simulated and measured results indicate that the antenna can operate at a UWB mode, two single band-notch modes, and a dual band-notch mode. Moreover, stable radiation patterns are obtained.

This article provides an account of the functorial correspondence between irreducible singular $G$-monopoles on ${{S}^{1}}\,\times \,\sum $ and $\vec{t}$-stable meromorphic pairs on $\sum $. A theorem of B.Charbonneau and J. Hurtubise is thus generalized here from unitary to arbitrary compact, connected gauge groups. The required distinctions and similarities for unitary versus arbitrary gauge are clearly outlined, and many parallels are drawn for easy transition. Once the correspondence theorem is complete, the spectral decomposition is addressed.

A wideband four element triangular dielectric resonator antenna (TDRA) has been designed and fabricated by using 50 Ω coaxial probe feed. The input and radiation characteristics of the proposed antenna have been extracted through Ansoft HFSS and CST Microwave Studio simulation software and compared with the experimental results. The simulated results have been in good agreement with the experimental results. The proposed antenna characteristics have also been compared with the same dimensions of the single element TDRA, and found enhancement in bandwidth with lower resonant frequency. Its performance has also been compared with same area (equal to proposed antenna) of single element TDRA. The proposed antenna provides nearly 37% bandwidth (|S11| < −10 dB) at a resonant frequency of 5.45 GHz with 4.76 dBi peak gain. The symmetry and uniformity in the radiation patterns is obtained consistently for the entire operating bandwidth. The proposed antenna shows consistently symmetric monopole type radiation pattern with low cross polarization for WLAN (IEEE 802.16) and WiMAX applications. The performance of the proposed antenna has been compared with some similar type of dielectric resonator antenna (DRA) shapes and it has been observed that TDRA is taking very less radiation area for giving better performance than other DRA shapes.

Three-dimensional compact volume internal antenna for universal serial bus (USB) dongle that covers hexa operating bands is proposed in this paper. The volume of the proposed USB dongle is 15×20×4 mm3; it is based on two connected monopoles, one of them is semi-circular monopole ended by three unit cells of meander-line and the other is a bent monopole with four unit cells of high-impedance wire. The proposed antenna is realized on a printed circuit board to reduce the fabrication costs. The coupling between the antenna elements broadens the operating bandwidth, which includes most of the wireless commercial service bands, GSM850/GSM900/UMTS/GSM1800/GSM1900/WCDMA2100/802.11b/g/LTE2600 (824–2690 MHz) as well as 802.11a/n (5150–5825 MHz). The antenna's simulated and experimental results are in good agreement.

Selon Arrow (1962), face à une innovation de procédé (réductrice de coût) une firme monopolistique subit l'effet de remplacement à savoir que la valeur qu'elle lui accorde est sous optimale et inférieure à la valeur de compétition technologique du brevet qui lui correspond. Nous transposons cette problématique dans le cadre d'une économie exploitant une ressource épuisable. En considérant les incitations à innover immédiatement, on peut alors montrer que le résultat de sous-incitation du monopole n'est pas toujours vérifié et parfois même se renverse : le monopole minier exhibe une propension à ne pas « s'endormir sur ses lauriers » lorsque la demande de la ressource présente une élasticité « fortement » croissante. En élargissant le résultat au cas des incitations dynamiques, nous montrons que le monopole adopte parfois plus vite l'innovation que la firme en concurrence.