Elliptical Monopole Research Articles

Research on Miniaturized UHF Sensing Technology for PD Detection in Power Equipment Based on Symmetric Cut Theory.

In answer to the demand for high sensitivity and miniaturization of ultra-high frequency (UHF) sensors for partial discharge (PD) detection in power equipment, this paper proposes research on miniaturized UHF-sensing technology for PD detection in power equipment based on symmetric cut theory. The symmetric cut theory is applied for the first time to the miniaturization of PD UHF sensors for power equipment. A planar monopole UHF sensor with a size of only 70 mm × 70 mm × 1.6 mm is developed using an exponential asymptotic feed line approach, which is a 50% size reduction. The frequency-response characteristics of the sensor are simulated, optimized and tested; the results show that the standing wave ratio of the sensor developed in this paper is less than 2 in the frequency band from 427 MHz to 1.54 GHz, and less than 5 in the frequency band from 300 MHz to 1.95 GHz; in the 300 MHz~1.5 GHz band; the maximum and average gains of the sensor E-plane are 4.76 dB and 1.02 dB, respectively. Finally, the PD simulation experiment platform for power equipment is built to test the sensor's sensing performance; the results show that the sensor can effectively detect the PD signals; the sensing sensitivity is improved by about 95% relative to an elliptical monopole UHF sensor.

Two Elements Orthogonally Placed UWB-MIMO for RADAR, Satellite and Terrestrial Communications

In this paper, a novel approach to design a compact ultrawideband (UWB) Multi-Input-Multi-Output (MIMO) antenna is presented. The proposed design consists of two elliptical monopoles placed orthogonal to each other for mutual coupling reduction. The design is integrated with three parallel coupled line strips for further mutual coupling reduction between the antenna elements. The physical dimension of the proposed design is 35 x 35 x 1.6 mm designed in low cost FR-4 substrate resulting in UWB characteristics in the WLAN range. The proposed design demonstrates good performance in the frequency range of 4.66 GHz to 12.42 GHz having large bandwidth of 7.76 GHz, with a mutual coupling of better than-20 dB in the entire band. The diversity performance, as measured by the correlation coefficient (ECC) and diversity gain (DG), is excellent, and within the acceptable range which proves that the proposed compact UWB MIMO antenna is a suitable candidate for RADAR, Satellite and Terrestrial Communications.

PD Flexible Built-In High-Sensitivity Elliptical Monopole Antenna Sensor.

In view of the insufficient signal detection sensitivity of Gas Insulated Switchgear (GIS), partial discharge (PD), ultra-high frequency (UHF), and failure to conform with GIS surface structure when the existing rigid stereo structure UHF sensor is built in, this paper, using rectangular patch antenna equivalent technique, trapezoidal ground plane technique, and coplanar waveguide (CPW) feed line index asymptotic linearization technique, conducts research on a flexible built-in high-sensitivity elliptic monopole antenna. The flexible antenna, with a thickness of only 0.28 mm, can be kept at a voltage standing wave ratio (VSWR) of less than three in the 300 MHz to 3 GHz band under the curvature radius of 0, 100, 300, and 500 mm, and at less than two in the 650 MHz to 3 GHz band. Through the true 220 kV-GIS partial discharge experimental platform built to analyze the high frequency electromagnetic wave detection performance of the built-in flexible antenna, it is shown that the flexible built-in high-sensitivity elliptical monopole antenna designed in this paper can effectively detect the characteristic signals of high-frequency electromagnetic waves emitted by partial discharges with an average discharge amount below 10 pC.

On Design of a Triple Elliptical Super Wideband Antenna for 5G Applications

A novel compact triple elliptical monopole antenna has been designed, analyzed and fabricated for super wideband applications. To enhance the impedance bandwidth, the author proposed a monopole antenna with a triple elliptical patch excited by a 50Ω triangular tapered microstrip feedline. Further improvement is achieved by optimally modifying the Defected Ground Structure (DGS) of the antenna. The proposed patch structure is mounted on a Roger’s RT-Duroid 5880 substrate (ϵ_r= 2.2, tan δ = 0.0009) and has compact physical dimensions of 27 mm × 29.5 mm. The fabricated antenna covers the frequency band from 1.91 GHz to 43.5 GHz for S₁₁ ≤ -10 dB with a fractional bandwidth of >183.17% and has a ratio bandwidth of 22.77:1. This extended bandwidth coverage permits the antenna to operate for wide range of application including 5G and Internet of Things (IoT). The proposed antenna has a very Bandwidth Dimension Ratio (BDR) of 5761.87 which makes it the best candidate for superwideband antenna. Far field measurements disclose an omnidirectional radiation pattern across the frequency of operation. Further, the farfield Radar Cross Section (RCS) is analyzed through simulation and it is to be noted that relatively low values are obtained through out the frequency of operation. In addition, the compactness of the proposed antenna is theoretically verified with the aid of fundamental dimension limit theorem.

A simple and effective broadband decoupling structure for UWB-MIMO antenna

Abstract A new type of closed square ring decoupling structure is proposed in this letter, which can effectively reduce the coupling of antennas. The designed antenna is composed of two elliptical monopoles and a common ground loaded with a broadband parasitic decoupling structure. Considering the impedance matching, each antenna element is changed from the original rectangular microstrip feed to a tapered microstrip feed and etched a circular slot on the elliptical monopole patch. By comparison with the original antenna without any decoupling structure, through loading the broadband decoupling structure on the ground, the antenna isolation is improved by 10 dB in most frequency bands. Comparing simulation and measurement results, the antenna achieves better than 25 dB isolation over the whole operating band (3.3–12 GHz). By manufacturing and testing the antenna designed in this article, the excellent performance parameters obtained also prove that the antenna can be used in portable devices.

Compact UWB‐to‐C band reconfigurable filtenna based on elliptical monopole antenna integrated with bandpass filter for cognitive radio systems

In this study, a compact configuration of frequency reconfigurable filtenna, designed by integrating a bandpass filter and with a monopole radiator, is demonstrated for achieving high-frequency selectivity along with compact size. The proposed filtenna can be efficiently tuned between ultra-wideband (UWB) and C-band states of operation. A bandpass filter, based on rectangular stepped impedance stub loaded multiple-mode resonator (MMR), is embedded to an elliptical monopole radiator to construct the filtenna circuit. The filtenna design approach leaves out the necessity of cascading an additional 50 Ω microstrip feed line in between the antenna and filter elements which makes the system more compact. The designed filtenna occupies 3.6–10.6 GHz band in its UWB state of operation and 3.63–4.70 GHz band in its C-band state of operation, respectively. The UWB operating state is intended for spectrum sensing application whereas the C-band operating state can be implemented for communication in a cognitive radio environment. The shifting between two operating states is controlled by appropriately switching the PIN diodes. An average peak gain of 2 dBi is observed within the passband. The overall size of the filtenna is optimised to 1.35 λ 0 × 0.96 λ 0 × 0.04 λ 0 ( λ 0 is calculated at 6.85 GHz). For validation purpose, the filtenna prototype is fabricated and characterised. A very close agreement is achieved with the suggested configuration.

A low‐profile quad‐port UWB MIMO antenna using defected ground structure with dual notch‐band behavior

A compact (45 × 45 × 1.6 mm3) ultrawide-band (UWB), multiple-input multiple-output (MIMO) design using microstrip line feeding is presented. The proposed design comprises four elliptical monopoles placed orthogonally on a cost-effective FR-4 substrate. In order to improve the impedance bandwidth and lessen the return loss of the MIMO antenna, defects in ground plane are created by etching symmetrical square slots and half-rings. Moreover, a different method (of unsymmetrical H-shaped slot with C-shaped slot) was proposed into the patch to introduce dual-band rejection performance from UWB at center frequency 5.5 GHz (covering lower WLAN as well as upper WLAN) and 7.5 GHz (X band). In addition, a stub is introduced at the edge of each defected ground structure to obtain isolation >–22 dB covering entire performing band from 2 to 16.8 GHz (where, S11 < –10 dB). The proposed design has miniaturized size, very low envelop correlation coefficient less than 0.1, stable gain (2-4 dBi except for notch bands). Furthermore, various MIMO performance parameters are within their specifications, such as diversity gain (= 10 dB), total active reflection coefficient (<–5 dB, and channel capacity loss (<0.35 bits/s/Hz). The presented design is optimized using the HFSS software, and fabricated design is tested using vector network analyzer. The experimental results are in good agreement with the simulation results.

Compact tri-band T-shaped frequency reconfigurable antenna for cognitive radio applications

This paper presents, new compact tri-band and broadband frequency reconfigurable antenna for cognitive radio applications. The proposed antenna consists of an Ultrawideband sensing antenna and reconfigurable communicating antenna at the same substrate. The sensing antenna is a UWB printed elliptical monopole antenna operates at frequency band from 2.72 to 23.8 GHz which can cover the entire UWB frequency band from 3.1 to 10.6 GHz and cover the broadband up to 20 GHz. The communicating antenna is a T-shaped frequency reconfigurable antenna operates on three bands of 7.925 GHz, 13.16 GHz, and 14.48 GHz under (S11≤-10 dB) with a fractional bandwidth of 14.55%, 6.2%, and 3.3% respectively. The proposed antenna used to operate in two modes one for cognitive radio applications to cover WiMAX, land, Fixed and Mobile satellite, Radar, and broadband applications. The frequency reconfigurability is obtained by using only one RF switch (PIN diode) for changing the operating frequency. The antenna overall dimensions are 42x30x1.6 mm3 printed on an FR-4 epoxy substrate with relative dielectric constant εr=4.3, loss tangent tan (δ)=0.002 and 50Ω microstrip line feed. The maximum obtained simulated gain is 8.5 dB at 13.16 GHz. The S11 is under -20 dB and coupling between the two antennas is less than -15 dB at the resonant frequencies.

Elliptical monopole based super wideband fractal antenna

AbstractAn elliptical monopole based third iterative fractal antenna for super wideband applications is investigated in this article. It consists of microstrip line fed three iterations of elliptical monopole in tree shaped manner and modified semielliptical ground plane. It has an impedance bandwidth of 0.65 to 35.61 GHz, that is, ratio bandwidth of 54.78:1. The overall footprint of the antenna is 170 × 150 mm2. A peak realized gain of 6.51 dB with an average gain of 3.24 dB is achieved. The investigated antenna has advantages of miniaturized dimensions, simple geometry, and wider bandwidth over previously reported structures.

UWB elliptical patch monopole antenna with dual-band notched characteristics

&lt;p class="Default"&gt;In this paper, a new approach to the design of an UWB monopole antenna with dual band-notched characteristics is presented. The antenna has the form of an elliptical monopole over a ground plane having an elliptical slot to achieve the UWB. The dual-band notch function is created by inserting a U-shaped and a C-shaped slots on the radiating patch, thus no extra size is needed. The proposed antenna shows a good omnidirectional radiation pattern across the band from 3.2 to more than 14 GHz. The dual band-rejection is for 4.88-5.79GHz centered at 5.4GHz and 7.21-8.46 GHz centered at 7.8 GHz. The antenna prototype using the FR-4 substrate with ε&lt;sub&gt;r&lt;/sub&gt;=4.3 has a compact size of 25mm×25 mm ×1.45mm. The fabricated prototype showed experimental results comparable to those obtained from the simulations.&lt;/p&gt;

Wide to multiband elliptical monopole reconfigurable antenna for multimode systems applications

Wideband-multiband reconfigurable elliptical monopole antenna is investigated in this paper. By having conventional elliptical monopole antenna, wideband operating frequency is obtained. With the combination of dual pairs of slotted arms and a band-pass filter on the ground plane of the elliptical monopole, multiband is achieved. Dual-band operating frequencies at 1.6 GHz and 2.6 GHz while wideband operates from 3.35 GHz to 9 GHz. Therefore, wide range of wireless communication systems is obtained from the proposed antenna to support the multiband mode (i.e. GPS and LTE) and UWB systems. Frequency reconfigurable is achieved by controlling the switches integrated on the antenna structure. Simulated results of reflection coefficient, radiation patterns and gain performance are presented. The proposed antenna design is suitable candidate for different wireless communication applications.

Computer simulation and physical phantom models for estimating the dielectric properties of rhinoceros tissue.

In vivo and ex vivo sensors have the potential to aid tracking and anti-poaching endeavours and provide new insights into rhinoceros physiology and environment. However, the propagation of electromagnetic signals in rhinoceros tissue is currently not known. We present simulation and agar models of the rhinoceros that allow the investigation of electromagnetic propagation by in vivo and ex vivo devices without the need for surgery. Since the dielectric properties of rhinoceros tissue have not been documented, the conductivity and permittivity of the skin, fat, muscle, blood and other organs are first approximated by means of a meta-analysis that includes animals with similar physical properties. Subsequently, we develop anatomical models that include dermal layers, internal organs and a skeleton. We also develop a flank model that serves as an approximation of the anatomical model in certain situations. These models are used to determine the viability of communication between an in vivo device and an ex vivo device attached to the hind leg of the animal. Two types of antenna (microstrip-fed planar elliptical monopole antenna and printed inverted-F antenna) and three feasible implant locations (back, neck and chest) are considered. In addition to the computer models, phantom recipes using salt, sugar and agar are developed to match the dielectric properties of each tissue type at the industrial, scientific and medical (ISM) frequencies of 403MHz, 910MHz and 2.4GHz. The average error between the measured and theoretically predicted dielectric values was 6.22% over all recipes and 4.49% for the 2.4 GHz recipe specifically. When considering the predicted efficiency of the transmitting and receiving antennas, an agreement of 67.38% was demonstrated between the computer simulations and laboratory measurements using the agar rhinoceros flank models. Computer simulations using the anatomical model of the rhinoceros indicate that the chest is the optimal implant location and that best signal propagation is achieved using the planar inverted-F antenna (PIFA). Using this configuration, the simulations indicate that communication between the implant and an ex vivo device attached to the hind leg is challenging but possible. Furthermore, we find that the inclusion of factors such as the density and temperature of the phantom materials were found to be critical to the achievement of good agreement between practice and simulation.

Shared‐aperture dual‐band orthogonally polarised antenna array for L‐band and S‐band applications

In this work, a novel dual-band orthogonally polarised, the shared-aperture array is proposed for the L-band and S-band frequencies. An elliptical monopole antenna is used as a radiating element in the proposed array. In this design, the common inter-element spacing is used for both the bands. Owing to this, L- and S-band arrays have the same number of elements. The L-band radiators are closely placed and designed taking the mutual coupling into account. The S-band antenna follows the traditional array design process. The inter-band coupling is reduced by using a metallic ridge in the reflector of the array. This array can be used in the dual-band radar applications. The proposed methodology offers the modular, low-profile and low-cost solution for a large array. To verify the proposed concept, a prototype array of 4 × 4 elements for each band has been fabricated and tested.

A compact cognitive radio UWB/reconfigurable antenna system with controllable communicating antenna bandwidth

ABSTRACTA low profile and compact size cognitive radio (CR) sensing/communicating antenna system is presented in this paper. A slotted elliptical monopole antenna is proposed as an ultra-wideband sensing antenna for the CR system, while the CR communication relies on a triangular reconfigurable monopole antenna. Two PIN diodes are attached to the reconfigurable antenna to provide four different wideband CR communications with variable bandwidths. The simulation and measured results are in good agreement, and they demonstrate that both antennas have an omnidirectional radiation pattern with acceptable gain values compatible with the portable CR devices. In addition, the results show low mutual coupling between the sensing antenna and the communicating antenna that reaches to values less than −16 dB for all operational modes of the PIN diodes.

A Compact Dual Band Gap Electromagnetic Band Gap Structure

In this communication, compact dual-bandgap two via double-slot-type electromagnetic bandgap (TVDS-EBG) structure is presented. The analysis of the TVDS-EBG structure is done by using the $LC$ model. Two resonance parallel $LC$ circuits per unit cell result dual-bandgap in the $x$ - and $y$ -directions. Compactness is achieved because of two via per unit cell, square slot, and inverse C-type slot on an EBG patch. The simulation of the unit cell TVDS-EBG is carried out using an eigenmode solution of Ansys high-frequency structure simulator. Simulated results are validated by experimental results. Simulated and experimental results prove that compared with a two-layer edge located via interdigital-EBG, edge located via-EBG, and Minkowski EBG, TVDS-EBG gives size reduction of 20.48%, 29.03%, and 31.25%, respectively, with a simple structure. The application of the proposed dual-bandgap TVDS-EBG for ultrawideband monopole antenna is also demonstrated. Simulated and measured results show that dual-band-notched can be obtained by using a unit cell of TVDS-EBG at fed line of an elliptical monopole antenna.

A compact disc loaded curved elliptical shaped ultra-wideband MIMO antenna

The ultra wide band (UWB) Multiple-Input- Multiple-Output (MIMO) antenna with coplanar waveguide (CPW) having size of 18 x 23 x 0.8mm3 is designed for ultra-wideband (UWB) applications. The designed MIMO antenna contains two symmetrical circular disc loaded curved elliptical monopoles on top of the substrate and common ground plane with Y slot and extended T-shaped stub on bottom of substrate. The T- shape stub is placed on the ground plane to have the better antenna impedance matching and to enhance the isolation between the two antenna ports. To further improve the isolation in between the ports 1 and 2, and also on the ground plane a Y-shaped slot is fixed. Good impedance matching (|S11| &lt; -10dB) in the range from 2.8GHz to 12 GHz is provided by the proposed antenna, and an enhanced isolation of -27dB, low ECC of below 0.002, an acceptable gain of about 7 dBi and an efficiency of above 90%. The obtained result proves that the designed antenna is more appropriate for the portable devices.

Flexible UWB organic antenna for wearable technologies application

New generations of printed flexible antennas are playing an important role in wireless communication systems. The ultra wide band and wearable possibilities are critical aspects of these kinds of antennas. In this study, the proposed antenna is an elliptical monopole fed by a coplanar waveguide; it uses a kapton substrate and it is optimised to work from 1 to 8 GHz. In the case of copper, a conductive nanocomposite material based on a polymer (polyaniline: PANI) and charged by multiwalled carbon nanotubes (MWCNTs) is exploited. The flexibility of both the kapton substrate and the nanocomposite (PANI/MWCNTs) provides the ability to crumple the antenna paving the way to potential applications for body-worn wireless communications systems. In this study, the performance of the antenna is investigated in terms of return loss, radiation patterns and gain for both crumpled and uncrumpled antennas. The results confirm that performance remains at a good level when the antenna is crumpled.

A frequency-reconfigurable elliptical monopole antenna for cognitive radio networks

In this paper, an elliptical disk monopole antenna with seven switchable states, including an ultrawideband (UWB) state and six narrowband states, is presented. It consists of an elliptical disk radiator to operate in the UWB mode for cognitive radio (CR) sensing. To operate in the narrowband mode, the antenna is fed through a defected ground structure (DGS) integrated microstrip line. Frequency reconfigurability is achieved by changing the DGS slot length using six electronic switches. The simple proposed design can cover a wide range of frequency bands from 0.75 to 12 GHz, has an omnidirectional radiation pattern with high gain, and is especially suitable as a CR front-end. The fabricated prototype shows good impedance matching in the specified frequency range.

A Wideband Printed Elliptical Monopole Antenna for Circular Polarization

A Wideband Printed Elliptical Monopole Antenna for Circular Polarization

CPW-FED PHI-SHAPED MONOPOLE ANTENNA FOR SUPER-WIDEBAND APPLICATIONS

A compact Phi-shaped monopole antenna for super wideband applications is proposed. It consists of a Phi-shaped radiator derived from a conventional elliptical monopole and quarter elliptical CPW ground plane. An impedance bandwidth from 3.5 to 37.2 GHz is achieved with a ratio bandwidth of 10 : 1. It provides an average peak realized gain of 3.5 dB with a group delay of less than 0.5 ns. The proposed antenna structure provides large bandwidth with the advantage of miniaturized dimensions compared to other SWB antenna structures.