Dielectric Constant Substrate Research Articles

Utilizing photonic crystal structure to design microstrip antenna with controllable dielectric constant substrate

A novel design method of microstrip patch antenna with photonic crystal substrate is proposed and analyzed. The method is different from the traditional one. Early work uses natural materials as the substrate to design microstrip patch antenna. In the work, dielectric cylinder arrays are designed based on periodic waveguide theory to realize the substrates with controllable dielectric constants. Meanwhile, applying dielectric cylinder array and microstrip antenna design theory, we designed and simulated a new type of antenna. The proposed antenna model is compared with homogeneous substrate structure antenna-based microstrip patch antenna and analyzed the radiation characteristics. The consistency of results shows that this method is feasible for antenna design. Afterwards, we fabricated a novel antenna with an equivalent dielectric constant of 2.94, which is further verify the feasibility of the method. Finally, the performance of designed antenna is analyzed with different cylinder height. The results show that the novel antenna design method maybe possess great significance to the design of high-gain miniaturized antenna.

Wideband tetraskelion dielectric resonator antenna

In this paper, a wideband tetraskelion dielectric resonator antenna with a low profile and high gain for the upcoming fifth generation (5G) communication applications is presented. The proposed DR antenna has been designed at the operating frequency of 26 GHz. The designed antenna is etched on Rogers RT/Duroid 5880 substrate of dielectric constant =2.2, with a thickness of 0.254mm. The DR material having a relative dielectric constant ( ) of 10 is used for a proposed design. The antenna was fed by using a 50-ohm microstrip line with slot coupling. The simulation and optimization have been performed by using the commercial software CST Microwave studio. The proposed structure exhibits a wide impedance bandwidth of 19.6% for |S11|< -10 dB from 24.5 to 29.6 GHz and peak gain of 9 dBi with the efficiency of 95% for complete bandwidth. The results show that an antenna is low profile and can be used for 5G wireless communication Applications.

Design and Simulation of Microstrip Multiband Antenna for Wireless Applications

This paper proposes a compact sized dual band microstrip patch antenna with microstrip feed line. The patch of antenna is a rectangular shaped patch which has a circular slot in the patch for multiband operations. This antenna covers frequency bands, centered at 2.4GHz, 3.3GHz, which is useful for the C-band and X-band operations. In this paper, a microstrip patch antenna with compact size of 21x17x1.6 mm in rectangular shape. This antenna is designed on FR4 substrate (Dielectric constant=4.4) of thickness h=1.6mm with ground of size 25x10 mm. The proposed structure were simulated on CADFEKO simulation software. This proposed antenna is suitable for multiband wireless communication systems and mobile equipments.

Substrate effect on the photoluminescence of chemical vapor deposition transferred monolayer WSe2

The substrate effect is an important issue in the properties of two-dimensional transition metal dichalcogenides (2D TMDs). Quantitatively determining the dependence of the photoluminescence (PL) emission properties and the excitonic behavior of single-layer 2D materials in a specific dielectric environment would provide helpful guidance for the rational design of substrates for high performance 2D TMD PL emission devices. Here, using a WSe2 monolayer on different substrates as a model system, it is demonstrated that the PL emission intensities can drastically change depending on the substrate effect. From the analysis of the excitonic behavior, the results reveal that the spectral weight between the neutral and charged excitons in the PL spectra is significantly modified by the substrate types, and the weight factor is dependent on the laser excitation density. The charged exciton binding energy is obviously negatively related to the substrate dielectric constant. Furthermore, the change trends of the binding energy of the monolayer WSe2 on different substrates are basically the same for the increase of the excitation density. These results suggest that the choice of the substrate plays a significant role in the modulation of the PL properties and exciton states of atomically thin WSe2; hence, substrate engineering should be carefully considered in the design of future 2D devices.

Triboelectric Nanogenerator With Enhanced Performance via an Optimized Low Permittivity Substrate

With electrical power generated from mechanical contact, triboelectric nanogenerators (TENGs) offer a promising route to realizing self-powered sensors. For effective usage, it is important to improve their limited power range (0.1–100 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) and this can be achieved by optimizing the output performance. Among the factors that confer higher performance are materials with a strong triboelectric effect together with low permittivity, but it is challenging to optimize both within a single material. This paper presents a solution to this challenge by optimizing a low permittivity substrate beneath the tribo-contact layer. Results are simulated over a range of substrate permittivities. The open circuit voltage is found to increase by a factor of 1.6 in moving from PVDF to the lower permittivity PTFE. Two TENG devices have been fabricated with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100\boldsymbol {\mu m}$ </tex-math></inline-formula> PET and PTFE substrates to compare performance. The experiments confirm that lowering the substrate dielectric constant (i.e. PET to PTFE) raises the open circuit voltage in line with simulation predictions.

Compact Slotted Microstrip Antenna for 5G Applications Operating at 28 GHz

ABSTRACT Microstrip antennas operating at 28 GHz for 5G applications are presented in this paper. Three different models of microstrip antennas with variations in slots are proposed. The operating frequency of 28 GHz is considered to be suitable for 5G antenna design. The low-cost FR4 substrate of dielectric constant of 4.4, thickness of 0.8 mm and loss tangent of 0.02 is used in the design. The performance of the antennas in terms of return loss, bandwidth, efficiency, gain, and directivity are analysed and compared. Slot configurations enhance the bandwidth and reduce the effective area. By introducing more number of slots in the design, the bandwidth gets enhanced than the existing design. The proposed designs are simulated using high-frequency structure simulator and antennas are compact in size with 7 × 7 mm.

A coplanar waveguide‐fed flexible antenna for ultra‐wideband applications

This paper presents a novel ultra-wideband (UWB) antenna printed on a 70 μm thick flexible substrate. The proposed antenna consists of a hybrid-shaped patch fed by coplanar waveguide (CPW). The ground planes on opposite sides of the feeding line have different height to improve antenna bandwidth. Simulation shows that the proposed antenna maintain wide bandwidth when changing its substrate's thickness and dielectric constant, as well as bending the antenna on a cylindrical foam. The proposed antenna is fabricated in laboratory with a simple and low-cost wet printed circuit board (PCB) etching technique. Measured bandwidths cover 3.06 to 13.58, 2.8 to 13.55, and 3.1 to 12.8 GHz in cases of flat state and bent with radii of 20 and 10 mm, respectively. Measured radiation patterns show the antenna is omnidirectional in flat and bent cases.

Compact 20-W GaN Internally Matched Power Amplifier for 2.5 GHz to 6 GHz Jammer Systems.

In this paper, we demonstrate a compact 20-W GaN internally matched power amplifier for 2.5 to 6 GHz jammer systems which uses a high dielectric constant substrate, single-layer capacitors, and shunt/series resistors for low-Q matching and low-frequency stabilization. A GaN high-electron-mobility transistor (HEMT) CGH60030D bare die from Wolfspeed was used as an active device, and input/output matching circuits were implemented on two different substrates using a thin-film process, relative dielectric constants of which were 9.8 and 40, respectively. A series resistor of 2.1 Ω was chosen to minimize the high-frequency loss and obtain a flat gain response. For the output matching circuit, double λ/4 shorted stubs were used to supply the drain current and reduce the output impedance variation of the transistor between the low-frequency and high-frequency regions, which also made wideband matching feasible. Single-layer capacitors effectively helped reduce the size of the matching circuit. The fabricated GaN internally matched power amplifier showed a linear gain of about 10.2 dB, and had an output power of 43.3–43.9 dBm (21.4–24.5 W), a power-added efficiency of 33.4–49.7% and a power gain of 6.2–8.3 dB at the continuous-wave output power condition, from 2.5 to 6 GHz.

Broadband Measurement of Substrate Complex Permittivity Using Optimized ABCD Matrix

In this paper, a novel two-transmission-line method based on optimized ABCD matrix for broadband and continuous substrate dielectric characterization is presented. The original single-line algorithm is firstly discussed and simulated, while the measurement shows that the extracted parameters are far from the actual values due to the presence of microwave connectors and transition mismatches. Therefore, a modified two-line algorithm based on the optimized ABCD matrix is proposed for ungrounded coplanar waveguide (UGCPW) configuration, which is very suitable for electroplating circuits with a consistent conductor layer on newly developed substrates. A comprehensive procedure to calculate the total line attenuation, phase number, characteristic impedance, substrate dielectric constant, and dielectric loss tangent is described. Since both conductor and radiation losses are taken into account, the extracted results show consistency within a single-digital percentage with the reference values. The analysis of the measurement uncertainty and the related uncertainty budgets for the derived dielectric results are also presented. The proposed method is expected to be applied to any transmission lines with arbitrary characteristic impedance, without a prior knowledge of substrate dielectric constant, and no additional calibrations are required other than the calibration kit for Vector Network Analyzer (VNA).

Integrated 60-GHz miniaturized wideband metasurface antenna in a GIPD process

We propose a miniaturized wideband metasurface antenna for 60-GHz antenna-in-package applications. With the glass integrated passive device manufacturing technology, we introduce a coplanar-waveguide-fed (CPW-fed) ring resonator to characterize the material properties of the glass substrate. The proposed antenna is designed on a high dielectric constant glass substrate to achieve antenna miniaturization. Because of the existence of gaps between patch units compared with the conventional rectangular patch in the TM10 mode, the radiation aperture of this proposed antenna is reduced. Located right above the center feeding CPW-fed bow-tie slot, the metasurface patch is realized, supporting the TM10 mode and antiphase TM20 mode simultaneously to improve the bandwidth performance. Using a probe-based antenna measurement setup, the antenna prototype is measured, demonstrating a 10-dB impedance bandwidth from 53.3 to 67 GHz. At 60 GHz, the antenna gain measured is about 5 dBi in the boresight direction with a compact radiation aperture of 0.31λ×0.31λ0 and a thickness of 0.06λ0.

Millimeter-Wave Substrate Integrated Waveguide Probe for Skin Cancer Detection.

This article presents an efficient and low-cost near-field probe, designed for early-stage skin cancer detection. Thanks to a tapered section, the device can achieve a sharp concentration of electric field at its tip. Moreover, the adoption of substrate integrated waveguide (SIW) technology ensures an easy and cheap fabrication process. The probe is realized on a high dielectric constant substrate (Rogers RO3210) that provides a good impedance matching with the skin, thus allowing to use the device in direct contact with it. This feature is essential to ensure that the proposed system can be adopted as a practical and effective tool for a fast scanning of many suspected skin regions. The probe is designed to operate at around 40GHz in order to achieve the penetration depth required to detect small cancer lumps in the skin, while preventing the fields from interacting with the underlying biological tissues. Furthermore, the concept of detection depth is defined with the goal of introducing a metric that is more suitable than the penetration depth to express the notion of the maximum distance from the skin surface at which a tumor can be detected. Thanks to a differential imaging algorithm, the probe is capable of working on every different skin types and body region. The proposed device has a lateral sensitivity and detection depth of 0.2 and 0.55mm respectively. The probe was designed and tested through simulations in CST Microwave Studio, as well as fabricated and validated through measurements on an artificial human skin phantom.

Design and Simulation of Slot Dimensions in Aperture Coupled Hemispherical Dielectric Resonator Antenna

Aperture coupled novel shaped Hemispherical Dielectric Resonator Antenna (HDRA ) and the various dimensions of slots are designed and analyzed by hfss software. The dielectric constant of dielectric hemisphere is € =9.8 and the substrate of dielectric constant is 2.96. aperture coupled novel shaped Hemispherical Dielectric Resonator Antenna (HDRA ) parameters are presented in this paper.. The effects of changing the slot length , slot width and position of slot on the antenna parameters and are presented in this paper, which are used for directive gain applications. As the change of slot dimension , it is observed that at the resonant frequency, it gives high gain and high negative return loss

A compact dual‐band dual‐mode antenna for GPS L1/L2 adaptive interference cancellation

AbstractA dual‐band dual‐mode microstrip antenna design is presented, with the application of adaptive interference cancellation in global positioning system at the L1 and L2 bands. The antenna consists of two stacked TM11 rings and two stacked TM21 shorted rings all fed by coaxial probes. By properly combining the two modes and utilizing both polarization components of each mode, up to three nulls can be steered at each frequency band to cancel interferers close to horizon. The concentric structure of the radiating patches in the proposed design allows for a compact antenna, which for a substrate of dielectric constant of 10 is only 0.33 λ in diameter at its lowest frequency of operation and can be further miniaturized on a higher dielectric constant substrate.

Design of Compact Hybrid Branch Line Coupler (BLC) for GSM Application

This paper presents a compact design of a hybrid branch line coupler (BLC) operating at 1.8 GHz frequency for the global system for mobile communication (GSM) applications. The miniaturization is achieved by using two short circuited stubs and one series transmission line (TL) instead of series quarter wavelength line of conventional BLC. The characteristic impedance of the shunt quarter wavelength section is optimized to improve the overall performances. Therefore, the proposed technique is 59% compact in size is compared to conventional BLC. The outputs at two ports (|S21| = |S31|) are 3.5 ± 0.3 dB with return loss (|S11|) and isolation (|S41|) is better than 20 dB. The prototype coupler is simulated using ANSYS HFSS EM simulator and fabricated on a substrate of dielectric constant (er) = 2.2, thickness (h) = 0.787 mm and loss tangent of 0.0009 and tested. The measured result is completely compiled with the simulated one.

A Metamaterial Inspired, Slotted Multiband Patch Antenna with Reconfigurability

In this letter the antenna is designed for achieving the multiband frequency configuration with the dimension of 26*26*1.6 mm3 with the use of substrate of dielectric constant of 4.4. It is capable of operating at the frequency of 3.9 GHz,5.8GHz and 6.7GHz, with a gain of 2.9dB,4.6dB,-1.5dB respectively. By using the method like DGS, Slots and SSRR structure, the design is able to generate and operate at the above mentioned frequencies. Furthermore by placing a metallic switch on the rectangular shaped slot the proposed antenna can also be used as reconfigurable antenna to produce different frequency

Sensor and Methodology for Determining Dielectric Constant Using Electrically Coupled Resonators

In this letter, a new sensor, theory, methodology, and experimental results of dielectric constant characterization of several planar samples under test (SUT) are presented. Each SUT is placed over a microstrip sensor that is based on a pair of electrically coupled resonators (ECRs). The proposed method determines the dielectric constant by using the electric coupling coefficient ( $k_{e}$ ) of a pair of coupled half-wavelength open-loop resonators. The methodology was successfully tested over a wide dielectric constant value substrates at 2.5 GHz, with substrates Diclad 880, Rogers 5870, Rogers 4003C, TMM10i, and Rogers 6010 resulting in high-accuracy percentages of 99.22%, 99.21%, 99.56%, 97.68%, and 98.60%, respectively.

Design of Compact MEMS Antenna Based on Photonic Crystal Structure

The miniaturized and integration antenna is designed to utilize high dielectric constant silicon substrate. Because of the inverse relation between planar size and dielectric constant, the proposed silicon antenna has very compact planar size. In order to enhance radiation efficiency of silicon antenna, the design method of photonic crystal antenna is proposed by applying periodical triangular lattice. Three dimensional MEMS manufacturing technology is used to fabricate the proposed antennas by photoetching, ICP through-hole etching and bonding processes, which can accurately realize cavity, air through-holes and other subtle and complicated structures. The experiment results demonstrate the MEMS antenna can obviously extend working bandwidth and improve radiation gain of the original antenna based on two dimensional triangle lattice photonic crystal structure.

Amplifier type active antenna at 2.45 GHz for wireless applications

In this paper, an active antenna is proposed, where microwave amplifier is directly integrated on passive antenna. The amplifier provides required RF power to the antenna, hence improves the system efficiency. This paper presents a slotted patch antenna, resonating at 2.45 GHz for Industrial Scientific Medical band, having excellent return loss of − 30 dB and radiation efficiency of 100%. The microwave amplifier was designed and optimized on AWR Microwave Office software for 11 dB gain and noise figure less than 2 at the frequency of 2.45 GHz. The proposed amplifier type active antenna was designed using FR4 substrate with substrate height, 1.6 mm and dielectric constant of er = 4.4. In active antenna, amplifier provides extra power to the antenna while electric parameters of active antenna are same, such as return loss is − 21.95 dB at 2.11 GHz and the improved bandwidth of 125 MHz. The passive antenna is designed, analyzed and optimized on IE3D Zeland software version 15.30.

Differential Shorted Patch Antennas

The design of a novel differential shorted patch antenna (DSPA) from a normal single-ended shorted patch antenna (SPA) is presented. It is shown that the DSPA has a smaller electrical size than the SPA. A transmission-line model is proposed to explain the reduced resonant size of the DSPA. A size reduction ratio of the DSPA to the SPA is defined and evaluated. It is found that the size reduction ratio mainly depends on the substrate thickness and the patch shape and slightly on the substrate dielectric constant. The simulated and measured results are given for both DSPA and SPA. The size reduction of the DSPA with respect to the SPA was experimentally validated.

Plasmon spectrum of graphene monolayer on substrate

Plasmon modes in monolayer graphene on substrate are analyzed taking into account the thickness of graphene and substrate material layer in the evaluation of Coulomb potential. It is shown that plasmon mode in graphene monolayer has linear dispersion in contrast to multilayer graphene in long-wavelength limit. The slope of plasmon spectrum is determined by the thickness and dielectric constant of substrate. Obtained results are in good agreement with experimental data and other theoretical considerations.