Showing papers on "Coaxial antenna published in 2018"
TL;DR: Measured reflection coefficients and radiation patterns demonstrate that the proposed reconfigurable filtering antenna is an eligible candidate for future multifunctional systems incorporating both UWB and WLAN systems.
Abstract: This communication presents a new reconfigurable filtering monopole antenna design with three switchable states for UWB/WLAN applications. The antenna has three independent ports for ultra-wideband state, 2.4 GHz WLAN narrowband state, and 5.8 GHz WLAN narrowband state, respectively. The narrowband state at 2.4 GHz is produced by a first-order microstrip filter using an open-loop resonator, and the narrowband state around 5.8 GHz is obtained by involving a third-order hairpin bandpass filter in the RF path. Frequency reconfiguration is achieved by RF path selection using dc controlled p-i-n diodes. As a result, narrowband filtering responses at desired frequency bands can be achieved. One antenna prototype is simulated, fabricated, and measured. Measured reflection coefficients and radiation patterns demonstrate that the proposed reconfigurable filtering antenna is an eligible candidate for future multifunctional systems incorporating both UWB and WLAN systems.
79 citations
TL;DR: In this paper, an extremely broadband circularly polarized (CP) antenna is presented, which consists of a crossed bowtie dipole loaded with four unequal parasitic cross slots, four parasitic bowtie patches, and four parasitic rectangular strips.
Abstract: An extremely broadband circularly polarized (CP) antenna is presented. The proposed antenna consists of a crossed bowtie dipole loaded with four unequal parasitic cross slots, four parasitic bowtie patches, and four parasitic rectangular strips. The cross slots can generate a CP mode due to the sequential phases of the crossed bowtie dipole. The parasitic bowtie patches are gap-coupled with two arms of the crossed bowtie dipole, and they are sequentially rotated along diagonals to generate an additional CP mode. The parasitic strips also generate one CP mode due to the sequentially rotated configuration parallel to the crossed bowtie dipole. By properly combining with two CP modes of the crossed bowtie dipole, broadband CP operation is achieved. The experimental and simulated results are in agreement, and the measured results show that the proposed antenna exhibits a very wide impedance bandwidth of 93.1% (2.21–6.06 GHz) and an excellent axial-ratio bandwidth of 90.9% (2.2–6.4 GHz). In addition, the proposed antenna produces a right-hand circular polarization with a peak gain of 8.6 dBi.
71 citations
TL;DR: In this article, an electrically actuated reconfigurable liquid-metal dipole antenna is presented using electrocapillary actuation, a 5 VDC signal can actuate the liquid metal Galinstan into five discrete states with varying polarizations and null directions.
Abstract: An electrically actuated reconfigurable liquid-metal dipole antenna is presented. Using electrocapillary actuation, a 5 VDC signal can actuate the liquid metal Galinstan into five discrete states with varying polarizations and null directions. Local surface-energy wells built into the polyimide fixture encasing the fluids enable metastable locking of the Galinstan, eliminating the need for a continuous dc bias voltage to maintain each state.
67 citations
TL;DR: In this paper, a novel ultra-wide-band tightly coupled dipole reflectarray (TCDR) antenna is presented, which consists of a wideband feed and a wide-band reflecting surface.
Abstract: A novel ultra-wide-band tightly coupled dipole reflectarray (TCDR) antenna is presented in this paper. This reflectarray antenna consists of a wideband feed and a wideband reflecting surface. The feed is a log-periodic dipole array antenna. The reflecting surface consists of $26 \times 11$ unit cells. Each cell is composed of a tightly coupled dipole and a delay line. The minimum distance between adjacent cells is 8 mm, which is about 1/10 wavelength at the lowest operating frequency. By combining the advantages of reflectarray antennas and those of tightly coupled array antennas, the proposed TCDR antenna achieves ultra-wide bandwidth with reduced complexity and fabrication cost. A method to minimize the phase errors of the wideband reflectarray is also developed and the concept of equivalent distance delay is introduced to design the unit cell elements. To verify the design concept, a prototype operating from 3.4 to 10.6 GHz is simulated and fabricated. Good agreement between simulated and measured results is observed. Within the designed frequency band, the radiation pattern of the TCDR antenna is stable and the main beam of the antenna is not distorted or split. The side lobe levels of the radiation patterns are below −11.7 dB in the entire operating band. It is the first time a tightly coupled reflectarray is reported.
60 citations
TL;DR: In this article, a compact antenna based on fractal and metamaterial loads techniques was proposed for wireless applications and the proposed antenna is suitable for reconfigurable antenna is shown in this paper.
Abstract: We have described a compact antenna based on fractal and metamaterial loads techniques. The microstrip patch antenna is assumed as a basic antenna and then the effect of fractal structures is implemented. The fractal patch is considered as a right-handed element and then by adding a left-handed element, the antenna miniaturization is achieved by using the metamaterial loads technique. The equivalent circuit is also used to describe the element effect on miniaturization and parametric models clarify them. The proposed antenna is modified for wireless applications and experimental results confirm our simulation results. In addition, we show that the proposed antenna is suitable for reconfigurable. By joining the unit cells together with various arrangements and changing the effective length, the various inductances can be obtained. Finally, by adding reconfigurable characteristic to the proposed antenna, the gain and radiation pattern can be controlled as shows in this paper. The patch antenna has low bandwidth and gain and so we have developed the patch antenna with defected ground to improve the bandwidth and the Frequency Selective Surface (FSS) is used to achieve higher gain and bandwidth. The final antenna is covering 2.4, 3.5 and 5.5 GHz with higher gain than the patch antenna.
56 citations
TL;DR: In this article, a dual-polarized omnidirectional antenna is proposed for mobile communication base station and 2.4 GHz wireless local area network applications by combining an inverted-cone monopole for vertical polarization (VP) and a modified cross bowtie dipole for horizontal polarization (HP).
Abstract: A wideband dual-polarized omnidirectional antenna is proposed for mobile communication base station and 2.4 GHz wireless local area network applications. An integrated design is achieved by combining an inverted-cone monopole for vertical polarization (VP) and a modified cross bow-tie dipole for horizontal polarization (HP). The proposed antenna has a compact size because the HP element acts as the HP radiating element and the ground plane for the VP element simultaneously. The proposed VP and HP antennas are excited by a $50~\Omega $ Sub-Miniature-A connector and a broadband feeding network, respectively. The overall volume of the proposed antenna is only $0.35\lambda _{0}\times 0.35\lambda _{0}\times 0.25\lambda _{0}$ (with $\lambda _{0}$ being the wavelength of the lowest frequency). Simulation results show that the dual-polarized omnidirectional antenna achieves a bandwidth (for $\vert \text{S}_{11}\vert dB) of about 41.5% (1.64–2.5 GHz) with an isolation of at least 25 dB and the gain variations at the center frequency in the horizontal plane are 0.7 dB for VP and 2.3 dB for HP. The good agreements between the simulation and measured results validate the proposed design.
47 citations
TL;DR: In this article, an integrated multiple-input-multiple-output (MIMO) antenna system is presented, which consists of a two-element printed inverted F-shape (IFA) MIMO antenna integrated with a 2-element frequency-agile annular slot-based antenna system.
Abstract: In this letter, an integrated multiple-input–multiple-output (MIMO) antenna system is presented. The proposed design consists of a two-element printed inverted F-shape (IFA) MIMO antenna integrated with a two-element frequency-agile annular slot-based MIMO antenna system. The IFA operates at the WLAN band, while the annular slots act as an isolation enhancement structure between the two IFA elements. Furthermore, the annular slots are tuned over the bands from 1.73 to 2.28 GHz with a minimum bandwidth of 60 MHz. The slots are made reconfigurable using varactor diodes. The integrated MIMO antenna system is designed on commercially available FR-4 substrate with dimensions $\text{50} \times \text{110} \times \text{1.56}\,\text{mm}^{3}$ . All the antenna elements are of small size, low profile, and planar in structure and hence can easily be accommodated in wireless devices for second-generation cognitive radio applications.
46 citations
TL;DR: In this paper, the impact of mutual coupling and edge effects on the gain pattern variation in the array was investigated, and the effect of this at system level is a decreased rate for all users for the zero-forcing MIMO detector, up to 20% for the patch array and 35% for a dipole array.
Abstract: Massive MIMO is considered a key technology for 5G. Various studies analyze the impact of the number of antennas, relying on channel properties only and assuming uniform antenna gains in very large arrays. In this paper, we investigate the impact of mutual coupling and edge effects on the gain pattern variation in the array. Our analysis focuses on the comparison of patch antennas versus dipoles, representative for the antennas typically used in massive MIMO experiments today. Through simulations and measurements, we show that the finite patch array has a lower gain pattern variation compared with a dipole array. The impact of a large gain pattern variation on the massive MIMO system is that not all antennas contribute equally for all users, and the effective number of antennas seen for a single user is reduced. We show that the effect of this at system level is a decreased rate for all users for the zero-forcing MIMO detector, up to 20% for the patch array and 35% for the dipole array. The maximum ratio combining on the other hand, introduces user unfairness.
40 citations
TL;DR: In this paper, the time domain analysis of an Ultra Wide Band antenna flexible circular monopole antenna is presented, which is fabricated on liquid crystalline polymer flexible substrate with a compact geometry that makes it suitable for wearable applications under different bending conditions.
Abstract: In this paper, the time domain analysis of an Ultra Wide Band antenna flexible circular monopole antenna is presented. The antenna is fabricated on liquid crystalline polymer flexible substrate with a compact geometry that makes it suitable for wearable applications under different bending conditions. The antenna is fed by coplanar waveguide transmission line and has a compact total size of 40 × 22 mm2. Moreover, the antenna has good radiation efficiency (97%) over the bandwidth. The presented antenna has a good performance over the operating spectrum for straight and bending configurations. The design principals along with simulation and experimental results are presented in this contribution.
36 citations
TL;DR: In this paper, a coplanar waveguide fed ring slot antenna is proposed for the generation of circular polarization, which can be improved by adding a stub antenna to the ring slot.
Abstract: In this article, a coplanar waveguide fed ring slot antenna is proposed for the generation of circular polarization. It is shown that the bandwidth can be improved by adding a stub. Characteristics mode analysis is used to understand the wideband behavior and generation of circular polarization in different antenna configurations. Parametric analysis is used to optimize the performance of the antenna. The proposed antenna is fabricated and the measured results are compared with the simulated performance. The measured impedance bandwidth (|S11| ≤ －10 dB) is 64.6% (2.25 GHz–4.4 GHz) and a 3 dB axial ratio bandwidth is 64.6% (2.25 GHz–4.4 GHz).
31 citations
TL;DR: In this article, a low cross-polarization periodic-slotted ridged substrate-integrated waveguide (RSIW) leaky wave antenna (LWA) array is presented.
Abstract: A low cross-polarization periodic-slotted ridged substrate-integrated waveguide (RSIW) leaky wave antenna (LWA) array is presented. Parametric constraints of the structure were investigated to realize a periodic leaky wave antenna (PLWA) with the ability of scanning from backward endfire into the forward quadrant. An appropriate multimode transverse equivalent network (TEN) is presented for the proposed antenna and values of leakage rate and phase constant for different parameters of the structure were extracted using the transverse resonance technique (TRT). The obtained results were compared to those achieved from HFSS software simulations. The open stopband in the broadside is eliminated using certain dimensions for the structure. By simultaneously manipulating a number of parameters, a variable {\alpha} and constant \b{eta} are resulted so that the desired sidelobe level (SLL) can be realized. The proposed structure was simulated and then manufactured. Simulation results show good agreement with measurement results.
TL;DR: In this article, a TE-polarized Bessel-beam antenna in the microwave range based on a leaky radial waveguide is presented. But the antenna is not suitable for high-frequency applications.
Abstract: In this paper, we present a transverse electric (TE)-polarized Bessel-beam antenna in the microwave range based on a leaky radial waveguide. According to the dispersion equation, an inductive sheet over a ground plane is needed. To achieve the inductive sheet, a grid structure printed on a dielectric substrate is designed. Besides, the radial waveguide is coaxially fed with a quasi-loop shaped structure to excite TE mode. The proposed antenna is investigated by simulation and measurement. In the measurement, a small loop is used to probe near magnetic field, and accurate measured magnetic intensity profiles are presented. The measurements show that TE-polarized Bessel beams can be launched within the nondiffractive range of 145 mm ( $2.803\lambda _{0}$ ) at 5.8 GHz.
TL;DR: Both simulation and experimental results show that the proposed antenna has the ability for liver tumor ablation, which offers faster heating rates in the heating center and more localized heating distribution than the conventional single-slot antenna.
Abstract: This paper presents a multi-slot coaxial antenna with a pi impedance matching network for liver tumor ablation. A multi-slot radiating probe was optimized by using the modified genetic algorithm to produce a near-spherical heating zone with significantly increased possibility of conformal treatment. A pi impedance matching network was designed to match the feeding transmission line and antenna without increasing antenna size. The reflection coefficient, ablation zone shape, specific absorption rate, and temperature were determined by a finite element electromagnetic simulation using COMSOL. Experimental validations were designed to evaluate the proposed antenna. Both simulation and experimental results show that the proposed antenna has the ability for liver tumor ablation, which offers faster heating rates in the heating center and more localized heating distribution than the conventional single-slot antenna.
TL;DR: In this article, a single-layer dual-broadband circularly polarised (CP) antenna that operates at 2.4, 5.2 and 5.8 GHz for wireless local area networks (WLAN) applications is proposed.
Abstract: This study proposes a single-layer dual-broadband circularly polarised (CP) antenna that operates at 2.4, 5.2 and 5.8 GHz for wireless local area networks (WLAN) applications. An annular-slot antenna loaded with a lightning-shaped slot for achieving good CP radiation in the WLAN 2.4 GHz band is initially studied. To cover the WLAN 5.2 GHz band as well, the inner circular patch of the aforementioned design is modified as an inner ring patch loaded with a notch and a narrow U-shaped strip. By further embedding a crescent parasitic element into the circular slot of the inner ring patch, the upper CP band is significantly broadened to cover the WLAN 5.8 GHz. Accordingly, the final design can exhibit two wide 3 dB axial ratio bands of 13.3% (2.24-2.56 GHz) and 16.9% (5.01-5.94 GHz), and their corresponding 10 dB impedance bandwidths are 25.9% (2.21-2.86 GHz) and 25.9% (5.05-6.54 GHz). With the advantages of compact size, low-cost, easy integration and dual-broad CP bands, the proposed designs are very attractive for modern wireless communication systems, especially for WLAN applications.
TL;DR: In this article, a two-segment rectangular dielectric resonator antenna is designed for ultra-wide application, which exhibits a maximum gain of 7.2 dBi at 10 GHz along with 95% of peak efficiency at 3 GHz.
Abstract: In this paper, a novel two-segment rectangular dielectric resonator antenna is designed for ultra-wide application. These dielectric resonator antennas, having different dielectric material, are placed side by side and are excited with common micro-strip feed. Further, the effect of defected ground is also investigated. The proposed structure offers a wide bandwidth of 131.24% for |S11| < –10 dB from 2.8–13.49 GHz catering needs of many wireless applications for S-band, C-band, X-band, WLAN, and WiMAX. The proposed antenna is fabricated and tested to validate the simulated results. This antenna exhibits a maximum gain of 7.2 dBi at 10 GHz along with 95% of peak efficiency at 3 GHz.
TL;DR: In this paper, a circularly polarized rectangular dielectric resonator antenna fed by a cross-aperture coupled spiral microstrip line is investigated, where a quarter wavelength section of microstrip lines is positioned between each arm of the cross slot in a spiral form to generate the circular polarization.
Abstract: In this article, a circularly polarized rectangular dielectric resonator antenna fed by a cross-aperture coupled spiral microstrip line is investigated. A quarter wavelength section of microstrip line is positioned between each arm of the cross slot in a spiral form to generate the circular polarization. The prototype of proposed antenna is fabricated and tested. The measured |S11| and 3-dB axial ratio frequency range is 31.74%, (2.65–3.65) GHz and 20%, (3.12–3.74) GHz, respectively and the measured total gain and left handed circularly polarized gain are 4.5 and 3.1 dB, respectively. The proposed antenna may be suitable for WiMAX applications.
TL;DR: In this article, a broadband microstrip CP antenna using single-fed technique is proposed for Global Navigation Satellite System (GNSS) operating at 1575.42 ± 10.23 MHz (GPS: L1 band), 1559∼1592 MHz (Galileo: E2-L1-E1 band, 1602 − 5.625 MHz (GLONASS: L 1 band) and 1559.052 ∼1591.788 MHz and 1610∼1626.5 MHz (
Abstract: This letter presents the design of a broadband microstrip CP antenna using single-fed technique. The feeding network is integrated within the coupling feed patch to simplify the structure. The proposed antenna is designed for Global Navigation satellite System (GNSS) operating at 1575.42 ± 10.23 MHz (GPS: L1 band), 1559∼1592 MHz (Galileo: E2-L1-E1 band), 1602 ± 5.625 MHz (GLONASS: L1 band) and 1559.052∼1591.788 MHz & 1610∼1626.5 MHz (BeiDou Navigation Satellite System B1 and L band). Another advantage of this antenna is the much wider bandwidth in both VSWR and 3 dB axial-ratio compared with traditional single-fed CP antennas. Details of design, simulated and experimental results of this CP antenna are presented and discussed. The measured results confirm the validity of this design which meet the requirement of GNSS applications.
TL;DR: A novel UWB feed network consisting of a ridged coaxial waveguide with eight inputs has been designed and optimized to achieve minimum reflections as well as desired radiation pattern over the frequency range of operation.
Abstract: A compact UWB (6–18 GHz) multibeam antenna system is proposed. Design procedures comprising of ridged coaxial waveguide, radome with lens properties, and biconical antenna are presented. A novel UWB feed network consisting of a ridged coaxial waveguide with eight inputs has been designed and optimized to achieve minimum reflections as well as desired radiation pattern over the frequency range of operation. The radiating element is a biconical antenna, redesigned and optimized to meet the requirements for radiation characteristics. Another notable improvement made by our design is to employ a radome, which not only enhances the mechanical stability of the biconical antenna and protects the structure, but also it acts as a lens that improves the directivity of the radiating element. Extensive optimization procedures have been applied to all parts of the antenna system to achieve the desired performance. The whole system has been simulated using HFSS full-wave simulator. The measurement results of the fabricated system are in good agreement with simulations.
TL;DR: In this paper, the authors presented a systematic numerical analysis of the microstrip-grid antenna aiming not only to explore the antenna performance limits in terms of frequency impedance bandwidth and maximum gain, but also to use this analysis as a starting point for further optimisation.
Abstract: This study presents a systematic numerical analysis of the microstrip-grid antenna aiming not only to explore the antenna performance limits in terms of frequency impedance bandwidth and maximum gain, but also to use this analysis as a starting point for further optimisation. The obtained antenna has dimensions 297mm × 210mm × 9.9 mm and at 2.41 GHz, has a maximum gain of 15.4 dB, which is very close to the directivity of an ideal, lossless aperture antenna with the same dimensions, at the same frequency. Measurements have shown that the antenna operates from 2.38 to 2.51 GHz (i.e. across the WiFi-band with a 5.32% frequency bandwidth relative to 50 Ω), with maximum radiation efficiency 98.2%, while the latter remains over than 91% for the whole WiFi-band, and finally has a measured half-power beamwidth of 18.5 and 34.5° in the horizontal and vertical planes, respectively. Thus, the antenna is suitable candidate for long-range WiFi links.
TL;DR: In this paper, a short pyramidal horn antenna with coaxial feed has been designed and fabricated with 52% bandwidth, which covers CDMA and GSM 900 bands, and the total length of the antenna including c...
Abstract: In this paper, a short pyramidal horn antenna with coaxial feed has been designed and fabricated with 52% bandwidth, which covers CDMA and GSM 900 bands. The total length of the antenna including c...
TL;DR: In this paper, a two-element MIMO multiband planar patch antenna with potential applications in the ISM bands is presented, where the antenna elements are placed adjacent to each other with a very small spacing of 0.004 λ 0 (λ being the free space wavelength of 433 MHz), confining the antenna dimensions to 51 × 50 mm2.
Abstract: A miniature two-element MIMO multiband planar patch antenna with potential applications in the ISM bands is presented. The elements of the antenna have been designed using a novel hybrid fractal geometry based on an altered Dragon Curve and the Inverted Koch. Reduced antenna dimensions are obtained with acceptable performance even at lower frequency ranges. The antenna elements are placed adjacent to each other with a very small spacing of 0.004 λ0 (λ being the free space wavelength of 433 MHz), confining the antenna dimensions to 51 × 50 mm2. The antenna resonates at the 433 MHz (ISM), 2.4 GHz (ISM), 3.9 GHZ (Fixed Satellite), 4.7 GHz (UWB) and 5.8 GHz (ISM) frequency bands. The antenna exhibits |S11| ≤ −10 dB, |S21| ≤ −16 dB, an ECC ≤ 0.01 for all operating frequencies, with circular polarisation at the 2.4 GHz and 5.8 GHz bands and linear polarisation at the others. The simulated structure was fabricated and tested, with the simulated and measured results displaying acceptable agreement.
TL;DR: A novel design procedure is proposed to overcome the narrow bandwidth characteristic of the monopole antenna by having sections with different lengths and radii as well as adding loads at two points along the antenna to optimize the radiation efficiency and bandwidth.
Abstract: A novel design procedure is proposed to overcome the narrow bandwidth characteristic of the monopole antenna. Having sections with different lengths and radii as well as adding loads at two points along the antenna makes it permissible to optimize the radiation efficiency and bandwidth of the monopole antenna. Particle swarm optimization (PSO) technique is used to determine the load values, their respective locations and the elements of the matching network. A bandwidth ratio of 5:l within the frequency range of 100–500 MHz is achieved. The total length of the antenna is 35 cm and the matching network is capable of handling RF power up to 100 W. The whole system is simulated with CST and ADS software. Measurement results of the fabricated antenna are in good agreement with simulations.
TL;DR: In this paper, a novel driver dipole is proposed to expand the working frequency band of the antenna, which can work from 3.75 to 10.4 GHz with good end-fire radiation gain ( > 4 −dBi) and low cross-polarization performances.
Abstract: This paper presents a uniplanar quasi-Yagi antenna with the coplanar waveguide feed line. A novel driver dipole is proposed to expand the working frequency band of the antenna. Due to the unique driver dipole, the proposed quasi-Yagi antenna can work from 3.75 to 10.4 GHz with good end-fire radiation gain ( > 4 dBi) and low cross-polarization performances. To verify the design, a prototype antenna is fabricated and measured. The experimental results are in accordance with the simulation results very well.
TL;DR: In vivo experiments suggest that this new MWA applicator could be successfully used to eliminate precise and small areas of tissue (around 20–30 mm2) and by modulating the power and time applied, it may be possible to increase/decrease the ablation area.
Abstract: Microwave ablation (MWA) by using coaxial antennas is a promising alternative for breast cancer treatment. A double short distance slot coaxial antenna as a newly optimized applicator for minimally invasive treatment of breast cancer is proposed. To validate and to analyze the feasibility of using this method in clinical treatment, a computational model, phantom, and breast swine in vivo experimentation were carried out, by using four microwave powers (50 W, 30 W, 20 W, and 10 W). The finite element method (FEM) was used to develop the computational model. Phantom experimentation was carried out in breast phantom. The in vivo experimentation was carried out in a 90 kg swine sow. Tissue damage was estimated by comparing control and treated micrographs of the porcine mammary gland samples. The coaxial slot antenna was inserted in swine breast glands by using image-guided ultrasound. In all cases, modeling, in vivo and phantom experimentation, and ablation temperatures (above 60°C) were reached. The in vivo experiments suggest that this new MWA applicator could be successfully used to eliminate precise and small areas of tissue (around 20–30 mm2). By modulating the power and time applied, it may be possible to increase/decrease the ablation area.
01 May 2018
TL;DR: In this article, the shape of a cylindrical antenna with 50-ohm feed and multiple air gaps was optimized to obtain the best impedance matching of the antenna-tissue system.
Abstract: Ablation is commonly used medical procedure for removal of liver tumors. It is minimally invasive technique that is based on the insertion of a thin needle antenna into malignant tissue and heating the region of interest by microwaves. The aim of this work is to optimize shape of a microwave antenna with 50-ohm feed and multiple air gaps. Fundamental sizes of cylindrical antenna should be changed, in particular dimensions of antenna slots and distances between them. Change of the geometry should be done in such a way as to obtain the best impedance matching of the antenna-tissue system. Therefore, 5 11 -scattering parameter will be used in the objective function. Importantly, the antenna operates at working frequency equal to 2.45 GHz.
TL;DR: In this article, a reflective metasurface which presents different reflection phases to different polarization waves is designed in a Fabry-Perot cavity (FPC) antenna, which can operate at 8.35-8.56 GHz (2.5%) and 9.5-10.1 GHz (6.1%) in y-polarization.
Abstract: A novel reflective metasurface which presents different reflection phases to different polarization waves is designed in this article. The metasurface is used as the ground plane of a Fabry-Perot cavity (FPC) antenna. The radiator of the FPC antenna is a dual-band patch antenna which has different polarizations in different bands, so by tuning the reflection phase of the metasurface correctly, the FPC antenna can work in two frequency bands. A prototype antenna is fabricated and measured. The measured results show that the antenna can operate at 8.35-8.56 GHz (2.5%) in x-polarization and 9.5-10.1 GHz (6.1%) in y-polarization. The maximum realized gains of the antenna in two bands are 17.6 dB at 8.75 GHz and 19 dB at 9.8 GHz. The measured results agree well with the simulated results which confirm the correctness of the design.
TL;DR: In this article, the phase velocity of each mode-transducing section was changed to improve antenna matching and the maximum achieved gain was 8.8 dB in 1.48 GHz frequency.
Abstract: Mode-transducing antenna transforms TEM mode into circular TE11 mode and then radiates it from an open-ended waveguide. Mode conversion is carried out by changing the phase velocity of each mode-transducing section. The maximum achieved gain of this antenna is 8.8 dB in 1.48 GHz frequency. An optimized dual dielectric window at the end of the waveguide improves the antenna matching. The measured results are in good agreement with simulation results.
TL;DR: An electron cyclotron resonance ion source model that uses a coaxial antenna to inject the RF power was simulated, and the corresponding hydrogen plasma densities of the ion source were calculated at different magnetic field distributions via a fluid model as discussed by the authors.