Ultra Wideband Spherical Self-Complementary Antenna with Capacitive and Inductive Loadings

The development of very small antennas significantly influences the miniaturization of handheld devices. A planar and symmetric antenna is built up. A capacitive loading for this planar inverted F antenna (IFA) is presented. For a further size reduction, an inductive loading is investigated. The method of moments (MoM) is used to model the antenna and measurements are carried out for verification.

A periodically loaded ultra wideband (UWB) bandpass filter based on the electromagnetic band-gap (EBG) concept is presented. Compact wideband filters with steep transition bands can be designed easily using this novel methodology. Unit cells in the EBG circuit model are realized by capacitive and inductive parallel loading of a transmission line. These unit cells are cascaded to realize bandpass filters whose bandwidth depends on the reactive loading of unit cells. The number of unit cells determines the steepness of the band edges of the filter. The main advantage lies in the fact that the size of unit cells can be small because electrical length of transmission line segments in unit cells can be chosen arbitrarily, hence the final filter structure becomes small in size. A microstrip filter with 60% bandwidth is designed and the physical size is compared with a conventional wideband bandpass filter designed with quarter wavelength admittance inverters.

Because the Josephson pair current in a weak-link superconductor junction is a nonlinear parametric function of junction voltage, the ac impedance seen by the junction influences both the response time to changes in bias and the dc voltage-current characteristics. The first effect is obvious; the second, considered here, has not been generally recognized. Both are relevant to device design. Two special cases which illustrate the basic principles involved are worked out in detail; they correspond, respectively, to ac capacitive and inductive loading. The results partly explain differences in the dc voltage-current characteristics of plane-parallel and point-contact junctions.

A generic integrated optoelectronic-to-VLSI packaging technology using silicon substrate and etched silicon optical submount has been developed and demonstrated. The miniature silicon submount that interfaces optical fiber with the optoelectronic component and the silicon substrate containing VLSI circuits is fabricated with double-sided nonplanar photolithography and anisotropic etching techniques. The advantages of this technology are: ability to interface optical information and circuits with VLSI in a single package; precision controlled capacitive, resistive, and inductive loading; minimized distance between optoelectronic components and electronic ICs, and between decoupling capacitors and active circuits; self-aligned fiber insertion; and highly automated manufacturing. These advantages translate to higher functional density and performance at a lower cost than conventional optoelectronic packaging technologies. >

In this work, an exponentially tapered microstrip antenna was implemented using a resistive loading technique in order to suppress the internal reflections. The inductive loading was realized by introducing slits on the antenna to improve radiation efficiency. Compared with a resistive-loaded antenna, the proposed antenna had an average improvement of about 6.2% in radiation efficiency within the range of 2?10.5 ㎓. In addition, the highest peak of the radiated short pulse from the proposed antenna became 45% greater than that of an antenna with resistive loading only.

Owing to the fascinating features of graphene material, graphene-based patch antennas have quickly attracted attentions in communication technologies for high-speed data transfer in terahertz band. Herein, we present in this chapter a careful study of a new ultra-wide band (UWB) graphene-based plasmonic terahertz (THz) antenna operating in the range of 7.4–8.4 THz, with a huge bandwidth of 1000 GHz. The resonant part of the antenna consists of a modified circular ring patch, designed on 2.4 µm-thick silicon laminate with a high permittivity of 11.9. The resonating frequencies and the antenna operation band can be controllable by adjusting the graphene layers’ chemical potential, where the desired UWB behavior is attained whit a chemical potential of 2 eV. The suggested antenna possesses a super compact geometry of 24 × 24 µm along with attractive radiation behavior in terms of gain (up to 5.5 dB) radiation efficiency (>97%). In addition, a high impedance matching is achieved which contributes in very low reflection coefficient of −53.5 dB. According to the outcomes realized, it can be inferred that the proffered THz antenna would be an excellent solution for various applications in terahertz regime, including the explosive detection, material characterization, homeland defense, security scanning, biomedical imagine, sensing, video rate imaging system and the upcoming short-range high-speed wireless indoor communications.

Partial discharge (PD) phenomenon in high-voltage (HV) apparatus is a warning symptom of insulation degradation that can eventually lead to equipment breakdown. The ultra-high frequency (UHF) or electromagnetic method has been widely adopted to monitor the insulation condition of HV power equipment such as power transformers. To detect PD occurrence on HV power transformers, the UHF method is preferable due to its high immunity to external interferences such as background noise and electromagnetic interferences from telecommunication. The UHF antennas are used in the UHF method to detect the electromagnetic waves emitted by PD events inside the power transformer tank. Many studies about the design of UHF antennas to detect PD on power transformers have been conducted previously. However, these UHF sensors are still facing noise disturbances especially for on-line partial discharge measurement, in presence of high noise levels. To address interference issues affecting the UHF sensor sensitivity, this paper presents a novel UHF PD sensor called rectangular microstrip patch antenna or simply patch antenna. This type of antenna has a simple structure, low cost for fabrication, and ultra-wideband (UWB) frequency enabling it to detect PD signals in a wide frequency range within the UHF range (300MHz-3GHZ). To design, simulate and optimize the UHF antenna, the HFSS software was used. The FR4-epoxy substrate having a thickness of 1.6mm, and a dielectric constant of 4.4 was used to design and simulate this rectangular patch antenna. The perfect electric conductor (PEC) was used on the rectangular patch, feedline, and ground plane of the designed patch antenna. The proposed antenna has a low reflection coefficient, low VSWR < 2, a wide bandwidth, as suitable gain, and directivity enabling this antenna to be a suitable and promising sensor for PD detection on power transformers.

An ultra-wideband (UWB) self-complementary planar bow-tie antenna (SCPBTA) is proposed. The antenna consists of a printed conical horn-shaped (CHS) radiator and a counterpart CHS slot etched on a rectangular ground plane. The printed CHS radiator is connected directly to the 50Ω microstrip line by bending the end portion of the feed line. As a result, the antenna has a simple structure which does not require impedance matching networks. The antenna with a compact size of 32×38×1.2 mm3 can cover UWB spectrum from 3.1 to 10.6 GHz. The simulation time- and frequency-domain results obtained from HFSS simulator package are verified by experimental measurements. Measured results for the reflection coefficient, far-field radiation patterns, radiation efficiency, gain, and group delay of the designed antenna over the UWB spectrum are presented and discussed. Measured data show good concordance with the numerical results. Also, the fidelity factor is calculated in both E- and H-plane by using CST Microwave Studio. The obtained results in both time- and frequency-domain indicate that the proposed SCPBTA is a good option for most practical UWB applications.

Internet of Things (IoT) based application requires integration with the wireless communication technology to make the application data readily available. In this paper, a modified meander shape microstrip patch antenna has been proposed for IoT applications at 2.4 GHz ISM (Industrial, Scientific and Medical) band. The dimension of the antenna is 40×10×1.6 mm 3 . The antenna design is comprised of an inverse S-shape meander line connected with a slotted rectangular box. A capacitive load (C-load) and parasitic patch with the shaped ground are applied to the design. Investigations show that the antenna designed with an inverse S-shape patch and connecting rectangular box in the microstrip line has a higher efficiency and gain compare to the conventional meander shape antenna. The C-load is applied to the feed line to match the impedance. Moreover, parametric studies are carried out to investigate the flexibility of the antenna. Results show that, the gain and efficiency can be improved through adjusting the rectangular box with applying parasitic element and the shaped ground. The parasitic element has high impact on the bandwidth of the antenna of 12.5%. The finalized antenna has a peak gain of -0.256 dBi (measured) and 1.347 dBi (Simulated) with 79% radiation efficiency at 2.4 GHz. To prove the efficiency and eligibility in IoT applications, the measurement of the power delivered and received by the antenna at 2.4 GHz is performed and compared with the results of a dipole antenna. The antenna is integrated with 2.4 GHz radio frequency module and IoT sensors to validate the performance. The antenna novelty relies on the size compactness with high fractional bandwidth that is validated through the IoT application environment.

In this paper, compact printed ultra-wide band (UWB) antennas with different number of arms are investigated and characterized numerically. As the antennas are proposed to be applied for UWB communication systems such as surface penetrating radar (SPR), they have to provide an ultra-wide band response due to narrow period pulse used by the application. The properties of antennas that are designed to have frequency range of 50–5000MHz for Voltage Standing Wave Ratio (VSWR) less than 2 and size-improved from the preliminary design are characterized with different number of arms and compared each other for some parameters including reflection coefficient (S 11 ), VSWR, gain and radiation efficiency. The optimization for antenna with additional arm is performed in terms of resistive loading application in all ends of arms and adding abrupt transitions onto additional arms. The proposed antennas are designed with 50Ω microstrip line feeding technique and deployed on FR-4 Epoxy substrate with overall size of 50mm × 41.2mm, relative permittivity of 4.3 and thickness of 1.6 mm. From the result, it shows that the proposed antennas achieve good performance i.e. reflection coefficient (S 11 ) &#60; −10dB in the frequency range of 50–5000MHz, where for the mono-arm antenna has a good achievement for lower frequency bands (&#60;1.1GHz) and higher frequency bands (>2.3GHz) whilst for the dual-arm antenna has a good response for pass frequency bands (1.1GHz–2.3GHz). The gain and radiation efficiency of antennas are almost similar each other where the gain of dual-arm antenna as well as radiation efficiency are higher than the mono-arm antenna for frequency ranges higher than 3.5GHz.

A printed ultra-wideband (UWB) multiple input multiple output antenna with isolation enhancement and pattern diversity is presented, which is based on characteristic modes (CM) for upcoming wireless mobile platforms. The presented antenna is composed of dual UWB antenna elements (AEs) – an antipodal Vivaldi and a circular-shaped monopole positioned on the two opposite edges of the antenna's rectangular-shaped ground surface. The two AEs are capable to stimulate distinct modes in the ground surface and therefore obtaining the required distinct radiation (far-field) patterns and highly isolated AEs without introducing any decoupling structure (DS). The measured results demonstrate that both AEs are UWB with an operating frequency from 2.6 to 11 GHz. The measured isolation is more than 30.1 dB with a maximum value of 55 dB in UWB. The peak realized gain is over 0.83 dBi. The radiation efficiency is greater than 75%. The Envelope Correlation Coefficient is &lt;0.08.

A compact planar ultra-wideband (UWB) monopole antenna with controllable dual-band-notched characteristics is presented in this paper. U-shaped inverted slot and vertical up C-shaped slot are embedded in the feed line and in the radiating patch, for rejecting WiMAX and WLAN frequency bands, respectively. Moreover, the bandwidth of each rejected band can be independently shifted by adjusting the dimensions of the corresponding band-notched structure. The proposed antenna with two rejected bands characteristics is successfully simulated, prototyped, and measured. The measured results show that the proposed antenna operates until upper 10.6 GHz for voltage standing wave ratio (VSWR) less than 2 and exhibits bands rejection of 3.20–4.1 GHz (24.66%) and 5.20–5.96 GHz (13.62%) frequency band. Furthermore, the proposed antenna shows good radiation characteristics, stable peak gain, and provides more than 80% radiation efficiency, on the entire UWB frequency range except in the notched frequency bands, which prospects the employment in the UWB communication systems.

In this paper, we show a UWB (Ultra Wide Band) high gain TEM (Transverse Electromagnetic) horn antenna with high directivity efficiency quality in operating bandwidth between 1GHz to 18GHz. Basing on good performance, the antenna can be applied as a feed source of many kinds of measurement systems, and can improve the resolution and contrast of microwave imaging. The measured results show that radiation efficiency is above 70 %, and the peak gain is about 10dBi.

This paper studies the effect of curved antenna performance on Ultra Wideband (UWB) characteristics, particularly on impedance bandwidth. A UWB antenna is designed, after which is curved and conformed onto cylindrical radius of 150 mm, 120 mm, 90 mm and 60 mm. The motivation of the study is to study the effectiveness of the antenna to be conformed onto non-planar structure applications, particularly on cylindrical body of air or land vehicles. It is observed that the degradation which occurs when the antenna is curved still adheres to the UWB characteristic of more than 500 MHz bandwidth. A circuit model is developed to understand the physics behind the antenna structure when it is curved or bent. The discontinuity of the antenna structure during the curving effect could be explained with the alteration of capacitive loading of the antenna, which is related to the electrical field of the antenna. The curved antenna proves to be suitable for UWB application and the results of its performance according to the UWB characteristics are discussed in detail.

ABSTRACTIn this paper, a new design of ultra‐wideband (UWB) antenna is reported for a microwave imaging system aimed to cover the UWB bandwidth from 3.1 to 10.6 GHz. The structure has a very simple Hibiscus petal pattern patch with tapered microstrip fed a line and partial trapezoid ground plane. The gap between the Hibiscus petal pattern patch and partial ground of the antenna are optimized to achieve wide impedance bandwidth. Results show that the antenna has a fractional bandwidth of about 120% from 3.04 to 11 GHz with S11 &lt; −10 dB with stable omnidirectional radiation pattern. The average gain of proposed prototype is 5.1 dBi and the radiation efficiency is about 85% on an average over the bandwidth. The fidelity factor for face to face is 0.8469 and for side by side is 0.9232 which represent the lower distortion of signal. The characteristics of proposed antenna are successfully simulated, prototyped and measured. Fairly good agreements between the simulations and measurements have been achieved. The reported antenna has a better impedance match and mutual coupling that provides a practical approach to realize the antenna for the UWB microwave imaging system. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1824–1831, 2016