Feed Line Of Antenna Research Articles

A Balanced Filtering Quasi-Yagi Antenna With Low Cross-Polarization Levels and High Common-Mode Suppression

A balanced planar quasi-Yagi antenna integrated with a bandpass filtering response is presented in this paper. The proposed balanced antenna consists of a balanced stepped-impedance microstrip-slotline transition structure, a driver dipole, a parasitic strip, and a bandpass filtering unit. A good differential-mode (DM) passband selectivity is formed by inserting a microstrip stub-loaded resonator (SLR) in the feed line of the quasi-Yagi antenna. This integration enables the antenna to achieve both compact size and high frequency selectivity. By controlling the dimensions of SLR, the central frequency and fractional bandwidth (FBW) can be easy to be adjusted. Meanwhile, the microstrip-slotline transition structure can achieve a good wideband common-mode (CM) suppression without affecting the DM ones, thus simplify the design procedure. The proposed antenna with low cross-polarization level and high CM rejection is found to be comparable to the conventional quasi-Yagi antenna. Furthermore, there are two radiation nulls on both sides of the passband to improve the selectivity effectively. In order to validate its practicability, the balanced antenna is designed and fabricated. The experimental results exhibit that the designed balanced filtering antenna features good filtering response, low cross-polarization level, and high CM rejection.

Active Compact Wearable Body Area Networks for Wireless Communication, Medical and IoT Applications

The development of compact wearable antennas and transceivers for communication, IoT (Internet of Things), and biomedical systems will be presented in this paper. Development of Compact efficient wearable antennas is one of the major challenges in development of wearable communication, IoT, and medical systems. The main goal of wireless body area networks (BANs), WBANs, is to provide continuously medical data to the physician. Body area network (BAN) antennas should be flexible, lightweight, compact, and have low production cost. However, low efficiency is the major disadvantage of small printed antennas. Microstrip antennas resonant frequency is altered, due to environment conditions, different antenna locations, and different system operation modes. These disadvantages may be solved by using compact active and tunable antennas. A new class of wideband active wearable antennas for medical applications is presented in this paper. Amplifiers may be connected to the wearable antenna feed line to increase the system dynamic range. Small lightweight batteries supply the bias voltage to the active components. An active dual polarized antenna is presented in this paper. The active dual polarized antenna gain is 14 ± 3 dB for frequencies ranging from 380 to 600 MHz. The active transmitting dual polarized antenna output power is around 18 dBm. A voltage-controlled diode, varactor, may be used to control the antenna electrical performance at different environments. For example, an antenna located in patient stomach area has VSWR (Voltage Standing Wave Ratio) better than 2:1 at 434 MHz. However, if the antenna will be placed on the patient back, it may resonate at 420 MHz. By varying the varactor bias voltage, the antenna resonant frequency may be shifted from 420 to 434 MHz. An ultra-wideband passive and active printed slot antenna may be employed in wideband wearable communication systems. The active slot antenna gain is 13 ± 2 dB for frequencies from 800 MHz to 3 GHz.

DESIGN OF RECTANGULAR WITH 3 SLOT MICROSTRIP ANTENNA FOR APPLICATION LTE 2.1 GHz

A rapid development of telecommunications technology, and over time, the existing network technologies continue to be developed. To create the latest technology called Long Term Evolution (LTE). With the technology that has a high transmission speed, of course, required new devices that can operate on this network. Antennas are needed on these networks is an antenna that is small and easily integrated. In this case, the right antenna to be used is the microstrip antenna. In this paper, which will be designed antenna is an antenna feed line rectangle shapes that can operate at a frequency of 2.1 GHz.

Design of compact frequency agile filter-antenna using reconfigurable ring resonator bandpass filter for future cognitive radios

AbstractIn this paper, a new miniaturized frequency agile filter-antenna with a wide reconfigurable frequency band is proposed for interweave cognitive radios (CRs). A tunable bandpass filter (BPF) composed of a symmetrical ring resonator is cascaded to the feed line of an ultra-wideband planar antenna. The structure of the proposed ring resonator BPF is simple and compact so that the total size of the proposed filter-antenna is smaller than that of a conventional system made of a separate antenna and BPF. The reconfigurability of the proposed filter-antenna is achieved by changing the operating frequency of the BPF by loading the ring resonator with a single varactor diode at its center. The fabricated prototype has successfully achieved a wide operational bandwidth of 1.43 GHz which covers continuous narrow bands from 4.65 to 6.08 GHz. Moreover, the operating tunable narrow bands have stable radiation characteristics. Good agreement between measurement and simulation results is demonstrated.

Low-Cost Aperture-Coupled 60-GHz-Phased Array Antenna Package With Compact Matching Network

A low-cost multilayer antenna-in-package solution, using the standard printed-circuit-board (PCB) process, is proposed for the 60-GHz-phased array system. The design procedure focuses on overcoming the fabrication restrictions and realizing a low-cost, broadband, compact and reliable package solution. The multilayer stack-up structure consists of three laminates and two bondply layers, with which the antenna element, vertical quasi-coaxial via transition, antenna feedline, power, and low-speed interfaces are realized. An aperture-coupled patch antenna with a compact fan-shaped feeding network and a vertical quasi-coaxial via transition are proposed, fabricated, and measured. For the single antenna element, including the vertical quasi-coaxial via transition, the measured fractional impedance bandwidth ( $\vert \text{S}11\vert dB) is 20.2%, and the measured peak gain is 6.9 dBi at 62 GHz. Based on the single antenna, a 16-element antenna package is realized in the dimension of 14 mm $\times14$ mm $\times0.925$ mm. Measurements show that each antenna element achieves a $\vert \text{S}11\vert $ less than −10 dB from 57.2 to 64.5 GHz, 4–7.5 dBi gain across all four IEEE 802.15.3c channels.

New Wideband Passive and Active Wearable Energy Harvesting Systems for Wearable Sensors

Abstract: Demand for green energy is in continuous growth. Wide band efficient wearable systems and antennas are crucial for energy harvesting wearable systems for medical and sport wearable sensors. Small harvesting antennas suffer from low efficiency. The efficiency of energy harvesting wearable systems may be improved by using active wearable harvesting systems with low power consumption. Amplifiers may be connected to the wearable antenna feed line to increase the system dynamic range. Novel active wearable harvesting systems are presented in this paper. Notch and Slot antennas are low profile and low cost and may be employed in energy harvesting wearable systems. The wearable harvesting system components are assembled on the same PCB. The notch and slot antennas bandwidth is up to 100% for VSWR better than 3:1. The slot antenna gain is around 3 dBi with efficiency higher than 90%. The antennas electrical parameters were computed in vicinity of the human body. The active antenna gain is 24 ± 2.5 dB for frequencies from 200 MHz to 900 MHz. The active antenna gain is 12.5 ± 2.5 dB for frequencies from 1 GHz to 3 GHz. The active slot antenna Noise Figure is 0.5 ± 0.3 dB for frequencies from 200 MHz to 3.3 GHz.

Electronically reconfigurable filtenna for cognitive radios

ABSTRACTA frequency tunable and bandwidth reconfigurable antenna with ring slot resonators embedded into its ground plane is presented. To achieve the bandwidth reconfigurability, two PIN diodes are inserted to couple or decouple two pairs of ring slot resonators from the antenna feed line. By switching the diodes on or off, the antenna can operate either in a wideband or narrowband mode. In the narrowband mode, two varactors are used to continuously tune the antenna operating frequency from 2.55 to 3.2 GHz. Due to the achieved bandwidths, the proposed structure can cover various bands used for LTE (1/2/7/33‐41 bands), WiMAX, and WLAN (802.11 b/g/n/s bands) applications. Similar radiation patterns with low cross‐polarization levels are obtained for different diodes states. The measured results show that the proposed design is potentially suitable for cognitive radio applications; in which the wideband mode is used for spectrum sensing while the narrowband mode for communicating over the selected channels. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:399–404, 2017

A New Triple Band Microstrip Fractal Antenna for C-band and S-band Applications

Recently research show that some parameters such as the shapes of antenna patch and the ground plane when geometrically altered produces changes in the current density distribution of the planar structure and consequently in the resonant modes. This paper presents a new microstrip fractal antenna using the technique of inserting slots of shape fractal in ground plane in order to increase the bandwidth and insertion discontinuities in the feed line to reach specific behaviors in three resonant modes. The FR-4 substrate with dimensions 85.0 x 85.0 x 1.57 mm3 is used. Also, it used different techniques of impedance matching in feed line of antenna with changes of the width of the transmission line in order to obtain a variation in the current distribution and consequently of the impedance bandwidth for S11 ≤ -10dB for C-band (3.625 GHz – 4.2 GHz) and S-band (2.0 GHz – 4.0 GHz). Good agreement between measured and simulated results is achieved. Proposed fractal microstrip antenna can be easily designed, built and applied in wireless communication.

Wideband to concurrent tri-band frequency reconfigurable microstrip patch antenna for wireless communication

This paper proposes a novel wideband to concurrent tri-band frequency reconfigurable microstrip antenna. The frequency reconfiguration is achieved by using a pair of PIN diodes in the antenna feed line to switch the antenna either in wideband mode or in concurrent tri-band mode. In order to improve the bandwidth and gain of the antenna for wideband operation, the properties of J-K inverter and split ring resonators are exploited. To demonstrate the versatility of this concept a prototype is fabricated and tested here. The tested results in wideband mode shows that the proposed antenna operates from 3.58 to –3.82 GHz, which is 4.08 times larger than the bandwidth of a simple microstrip patch antenna. In the concurrent tri-band mode frequency tuning is done by microstrip open stub at 1.5 GHz, 1.9 GHz, and 3.5 GHz. Gain of the proposed antenna is better than 2.7 dB in wideband mode and 2.7 dB in concurrent tri-band mode.

The Effect of a Single and Combined Slot Generated At the Upper and Lower Part of the Rectangular Patch Antenna Performances

<div><p><em>The paper investigates the effect of the slot made on the radiating plane (top) and ground plane individually and their effect when made on both the surfaces on the antenna performance. The paper further investigates effect of the slot on gain, frequency and radiation pattern made at different angles more specifically at angles of </em><em>0°,45° and 90° to the antenna feed line.</em></p><p><em>The antenna has been designed using advanced system design (ADS).</em></p></div>

The impact of frequency on the performance of microwave ablation

Purpose: The use of higher frequencies in percutaneous microwave ablation (MWA) may offer compelling interstitial antenna design advantages over the 915 MHz and 2.45 GHz frequencies typically employed in current systems. To evaluate the impact of higher frequencies on ablation performance, we conducted a comprehensive computational and experimental study of microwave absorption and tissue heating as a function of frequency.Methods: We performed electromagnetic and thermal simulations of MWA in ex vivo and in vivo porcine muscle at discrete frequencies in the 1.9–26 GHz range. Ex vivo ablation experiments were performed in the 1.9–18 GHz range. We tracked the size of the ablation zone across frequency for constant input power and ablation duration. Further, we conducted simulations to investigate antenna feed line heating as a function of frequency, input power, and cable diameter.Results: As the frequency was increased from 1.9 to 26 GHz the resulting ablation zone dimensions decreased in the longitudinal direction while remaining relatively constant in the radial direction; thus at higher frequencies the overall ablation zone was more spherical. However, cable heating at higher frequencies became more problematic for smaller diameter cables at constant input power.Conclusion: Comparably sized ablation zones are achievable well above 1.9 GHz, despite increasingly localised power absorption. Specific absorption rate alone does not accurately predict ablation performance, particularly at higher frequencies where thermal diffusion plays an important role. Cable heating due to ohmic losses at higher frequencies may be controlled through judicious choices of input power and cable diameter.

Microstrip antenna miniaturization with fractal EBG and SRR loads for linear and circular polarizations

In this paper, combination of electromagnetic band gap (EBG) and split-ring resonator (SRR) loads with fractal formation for miniaturization of microstrip antenna is noticed. Here two different shapes of antenna have been studied with two well-known metamaterial structures as parasitic elements. A conventional microstrip antenna, which is surrounded by four EBG unit cells, is chosen as the first antenna. It has an effective resonance at 2.5. The Minkowski fractal method is applied to EBG unit cells in this stage. The Minkowski fractal structure is implemented for accession of effective capacitance in EBG unit cells. The second antenna frequencies are 2.5 and 5.9 GHz. It contains a slot structure with four SRRs, used for making parasitic elements and for achieving multi-band characteristic. The fractal method is used to improve the inductance of SRR structure by increasing the effective length of microstrip line. At this stage, the applied fractal structure has been modified, so that the frequency of wireless application could be achieved. In the last step, by some changes in feed line of the slot antenna, circular polarization (CP) is obtained for the second antenna, which shows that SRR load can be helpful for making the CP.

Reconfigurable and Tunable Filtenna for Cognitive LTE Femtocell Base Stations

A single-port uniplanar antenna with a built-in tunable filter is presented for operation in multiple LTE bands for cognitive femtocell applications. The antenna is based on a monopole microstrip patch fed by coplanar waveguide. The frequency reconfigurability is achieved by using two PIN diodes to couple or decouple a ring slot resonator filter from the antenna feed line. By switching the PIN diodes, the proposed design can operate in either wideband or narrowband modes. When the antenna operates in the narrowband state, two varactor diodes are used to continuously tune the narrowband frequency from 2.55 to 3.2 GHz, while the wideband state is obtained over the 1.35–6.2 GHz band. The diodes and their biasing networks have nearly no severe effect on the antenna characteristics. Prototypes of the proposed structure using ideal and real switches, with and without varactors, are fabricated and tested. Measured and simulated results are in good agreement, thus verifying the good performance of the proposed design. The obtained results show that the proposed antenna is very suitable for cognitive radio applications, in which the wideband mode is used for spectrum sensing and the narrowband mode for transmission at different frequency bands.

Fast and accurate synthesis of electronically reconfigurable annular ring monopole antennas using particle swarm optimisation and artificial bee colony algorithms

The synthesis of a simple electronically reconfigurable annular ring monopole antenna using a designing optimisation process based on particle swarm optimisation (PSO) and artificial bee colony (ABC) algorithms is proposed. Several antenna dimensions are selected as objective functions of PSO and ABC and their best solutions are considered as the optimised dimensions of the antenna geometry. Two radio-frequency p–i–n diodes, connecting the antenna feeding line to two microstrip stubs are used to change the antenna frequency response from ultra-wideband (UWB), from 3.1 to 10.6 GHz, to narrowband (NB) operation about 5.8 GHz. The antenna design and simulation are performed using Ansoft high-frequency structure simulator software. PSO and ABC algorithms are written in Java language. Thereafter, antenna prototypes are fabricated and measured for validation purposes. Simulation and measurement results are obtained showing good agreement. The measured optimised impedance bandwidths of the UWB and NB bands are up to 128 and 23%, respectively. Additionally, simulated and measured radiation patterns are very similar when the reconfigurable antenna is operating in OFF-state (UWB sensing antenna) and in ON-state (NB transmitting antenna) modes, indicating the proposed antenna geometry as a promising candidate for applications such as UWB and cognitive radio.

A Broadband Hybrid Water Antenna for Hand-Portable Applications

In this letter, a broadband, low-profile, hybrid water antenna is proposed. The hybrid structure combines the resonance of the dielectric resonator (DR) and the resonance of the monopole together to cover the required frequency band. The unique features of the water DR are transparency, reconfigurability, and liquidity, which allows complex structures (including the antenna feeding line) to be placed and tuned inside water easily. Both the computer simulations and measurements are conducted to validate the antenna performance. The proposed antenna has a -6 dB impedance bandwidth from 430 to 900 MHz (a fractional bandwidth of 70%). Compared to other antennas for this band, this new antenna has a wider bandwidth, more compact size, and simpler structure. It is therefore a very promising candidate for hand-portable applications such as DVB-H (470-862 MHz).

Optically Controlled Reconfigurable Filtenna

This work is regarding the development of a novel antenna called optically controlled reconfigurable filtenna, which is based on the integration of a broadband printed antenna with a bandpass reconfigurable RF filter. The filter is designed by applying defected microstrip structure (DMS) technique and positioned in printed antenna feeding line in order to keep the same size of the original antenna. The filtenna bandwidth is optically reconfigurable by using two photoconductive silicon switches excited by CW laser at 808 nm. Numerical results rely on independent and switchable operational modes through the 2.4 and 5.1 GHz ISM bands, whereas measurements demonstrate two reconfigurable modes based on single-band/dual-band operation over the same frequency bands. The proposed device is validated by theoretical, numerical, and experimental results.

Liquid‐metal frequency‐reconfigurable slot antenna using air‐bubble actuation

Liquid metal actuated by pressure-driven air bubbles is guided within channels to dynamically reconfigure the length of the radiating aperture and feed line of a slot antenna. The gallium-based liquid metal is held in position by air bubbles, and liquid-metal motion is induced when a pressure differential is created. In contrast to conventional hydraulic or pneumatic actuation of gallium-based liquid metal, the pressure actuation described here is reversible and repeatable, as the liquid metal is enveloped by a thin layer of NaOH solution, which acts as a slip layer and reduces any metal oxidation. The slot antenna achieves a 26% tunable bandwidth with a contiguous range from 1.42 to 1.84 GHz for which the S 11 is <;-10 dB. The peak gain ranges from 4.8 dBi in its lowest-frequency state to 4.1 dBi in its highest-frequency state.

Miniaturised printed elliptical nested fractal multiband antenna for energy harvesting applications

This study presents the design, optimisation, simulation and fabrication of a novel printed elliptical nested fractal (planar) antenna for multiband operation. The proposed antenna is intended to function as the receptor element in radio-frequency energy harvesting applications. The simple microstrip structure and the compact size of the antenna ease its fabrication and allow it to be integrated with other electronic circuitry. It consists of nested elliptical structures fed by 50 Ω microstrip line with complementary elliptical ground along with rectangular ground plane. The added Hilbert structures at both sides of the antenna feeding line on the top layer enhance its performance to operate in multi-frequency bands. This antenna exhibits good radiation and reflection characteristics at 910 MHz (global system of mobile (GSM 900)), 2.4 GHz (Bluetooth/wireless local area network), 3.2 GHz (Radiolocation, third generation (3G)), 3.8 GHz (for long-term evolution, 4G) and additional 5 GHz band (wireless fidelity signals). The overall dimension of antenna is 41 mm (width) × 44 mm (length) × 1.778 mm (thickness). To the best knowledge of the authors, this is the widest bandwidth antenna to be developed at these small dimensions covering major standards from 900 MHz up to 6 GHz for electromagnetic energy harvesting applications.

Band-Reconfigurable Monopole Antenna for Cognitive Radio Applications

ABSTRACTA single-port compact planar integrated ultra-wideband (UWB)/frequency-reconfigurable narrowband monopole antenna is proposed. Reconfigurability is achieved by inserting a varactor-diode tuned bandpass filter into the feed line of the UWB antenna. The antenna operation is changed from wideband to narrowband by activating PIN diode switches in the structure. Good tunability obtained within a wide sensing band of 2.2–6 GHz is significant for cognitive radio applications.

WIDEBAND ANTENNA WITH RECONFIGURABLE BAND NOTCHED USING EBG STRUCTURE

A wideband antenna with band notch function using electromagnetic bandgap (EBG) structure is proposed. The antenna is capable of reconfiguring up to three band notch operation. Three EBGs are aligned underneath the feed line of the wideband antenna. The transmission lines over EBGs unit cells perform as a band stop filter. A switch is placed on each of the EBG structure, which enables the reconfigurable band stop operation. The simulated and measured reflection coefficients, together with the radiation patterns, are shown to demonstrate the performance of the antenna.