Thick Dielectric Substrate Research Articles

Modeling of Microstrip line Gap Discontinuity on Multilayer Substrate

In this paper, the modeling of microstrip line gap discontinuity on multilayer semiconductor substrate is presented. The reflection coefficient and transmission coefficient are computed from the equivalent lumped circuit model of microstrip line gap discontinuity. The lumped circuit elements- capacitance, inductance and resistance are calculated using closed-form expressions in term of the gap discontinuity, width of microstrip line and dielectric substrate thickness. Static Spectral Domain Analysis (SDA) method is used to compute characteristic impedance of microstrip line.

Fabrication of compact substrate integrated waveguide dual band bandpass filter using complementary split-ring resonators for C and X band applications

This article presents a compact dual-band Bandpass Filter(BPF) based substrate integrated waveguide(SIW) used for C and X band applications. Complementary split-ring resonators(CSRR) are loaded into the waveguide surface to obtain more advantages of compactness and good performance. The SIW cavity undergoes initial optimization utilizing the powerful genetic algorithm, renowned for its robustness in solving complex problems, before proceeding to simulation with Ansys HFSS software with loaded CSRRs. The filter displays two passbands: the first has a bandwidth of 2 GHz and resonates at 6.8 GHz, while the second has a bandwidth of 5,55 GHz and resonates at 10.3 GHz. Moreover, with two resonance frequencies, the developed BPF has the benefit of low insertion loss(S21=-1.7dB and -1.9 dB) and improved return loss: (S11=-24dB and -22 dB) respectively. Furthermore, the proposed combination not only allows the implementation of a forward-wave passband propagating below the characteristic cutoff frequency of the waveguide but also exhibits good rejection, demonstrated by the presence of two transmission zeros with rejection of -16 dB and -19 dB, attained at 7.4 GHz and 14.8 GHz respectively. The proposed SIW BPF was designed using a 0.6mm thick FR4 dielectric substrate measuring 13mm × 15mm. The filter is manufactured to validate the concept and the measured results agree well with the simulation. With all these advantages: compact size, high rejection, and good filtering response, the proposed SIW BPF became suitable for microwave applications.

Comparison of a Circular Patch Unit Cell Performance for Reflector Applications between Using FR4 and F4BMX220 Substrates at 3.5 GHz Frequency

This paper presents a performance comparison of the circular patch unit cell as a unit cell for reflector application at 3.5 GHz frequency using a dielectric substrate between FR4 and F4BMX220 substrates. A circular patch is chosen as the unit cell of a reflector because it is commonly used, fabricated, and has a wider bandwidth compared to other structures. A performance comparison of the circular patch on both dielectric substrates is presented in a graph of S-parameters, reflection phase, and operating bandwidth, as well as in the table of dimensions, where the result is performed by simulation using CST software. Based on the simulated results, the F4BMX220 has a better performance compared to the FR4 in terms of the reflection value, operating bandwidth, and dielectric substrate thickness. However, a circular patch diameter when using the F4BMX220 is bigger than when using the FR4 substrate because the FR4 substrate has a higher dielectric constant than the F4BMX220, which is twice the F4BMX220 dielectric constant. Also, the F4BMX220 substrate has a narrower bandwidth compared to the FR4 substrate, which is a difference of around 0.1 GHz. The circular patch when using the F4BMX220 substrate has 0.96 of a reflection value, 0.007 of an absorption value, -6.77° of the reflection phase, and 0.24 GHz of the operating bandwidth at the normal incident wave angle (0°). Also, it can be properly worked if the incident wave angle is moving until 60°. The F4BMX220 substrate has the best performance compared to the FR4 substrate because the reflection value is much better value, even at the incident wave angle of 60°.

New Complementary Resonator for Permittivity- and Thickness-Based Dielectric Characterization.

The design of high-performance complementary meta-resonators for microwave sensors featuring high sensitivity and consistent evaluation of dielectric materials is challenging. This paper presents the design and implementation of a novel complementary resonator with high sensitivity for dielectric substrate characterization based on permittivity and thickness. A complementary crossed arrow resonator (CCAR) is proposed and integrated with a fifty-ohm microstrip transmission line. The CCAR's distinct geometry, which consists of crossed arrow-shaped components, allows for the implementation of a resonator with exceptional sensitivity to changes in permittivity and thickness of the material under test (MUT). The CCAR's geometrical parameters are optimized to resonate at 15 GHz. The CCAR sensor's working principle is explained using a lumped-element equivalent circuit. The optimized CCAR sensor is fabricated using an LPKF protolaser on a 0.762-mm thick dielectric substrate AD250C. The MUTs with dielectric permittivity ranging from 2.5 to 10.2 and thickness ranging from 0.5 mm to 1.9 mm are used to investigate the properties and calibrate the proposed CCAR sensor. A two-dimensional calibration surface is developed using an inverse regression modelling approach to ensure precise and reliable measurements. The proposed CCAR sensor is distinguished by its high sensitivity of 5.74%, low fabrication cost, and enhanced performance compared to state-of-the-art designs, making it a versatile instrument for dielectric characterization.

SRR inspired modified psi shaped perfect metamaterial absorber for C-band application

In this research article, a compact and simple design of polarization insensitive perfect metamaterial absorber (PMA) is offered. The design is optimized to target the two mid frequencies of C-band for satellite communication. This novel design is a congress of two modified psi shaped resonators which are surrounded by a split ring resonator (SRR) and an octagonal split ring resonator (OSRR). Dielectric material FR-4 of loss tangent 0.025 and thermal conductivity 0.3 WK-1m−1 is used as substrate whereas the copper (annealed) of thermal conductivity 401 WK-1m−1 and electrical conductivity 5.8 × 107 Sm−1 is used for back copper plate and resonators. This is a compact unit cell of electrical dimension 0.268λ × 0.268λ with 1.6 mm thickness of dielectric substrate and 0.035 mm thickness of bottom copper sheet. The proposed PMA is simulated within the microwave frequency range 5 GHz to 10 GHz with commercially available FIT based high-performance3D EM analyserCST microwave studio suite. The simulation result yields two resonance peaks at 6.15 GHz and 7.36 GHz with fantastic absorption rate 99.99% and 99.40%, respectively. The presented PMA shows polarization insensitivity up to 45° and oblique wide angle incidence up to 75°. Moreover, the simulated outcome is validated by some trusted validation processes; for example- equivalent LC circuit by advanced design software (ADS) and FEM based high-frequency structure simulator (HFSS). A very negligible amount of deviation of resonance frequencies are observed in ADS and HFSS results compared to CST simulated result. Different types of array combinations are also simulated to test the stability of the result and to check the coupling effect. This C-band PMA is recurrently deployed in satellite communication band, defense, security, and stealth coating equipment.

Design of high gain base station antenna array for mm-wave cellular communication systems

Millimeter wave (mm-Wave) wireless communication systems require high gain antennas to overcome path loss effects and thereby enhance system coverage. This paper presents the design and analysis of an antenna array for high gain performance of future mm-wave 5G communication systems. The proposed antenna is based on planar microstrip technology and fabricated on 0.254 mm thick dielectric substrate (Rogers-5880) having a relative permittivity of 2.2 and loss tangent of 0.0009. The single radiating element used to construct the antenna array is a microstrip patch that has a configuration resembling a two-pronged fork. The single radiator has a realized gain of 7.6 dBi. To achieve the gain required by 5G base stations, a 64-element array antenna design is proposed which has a bore side gain of 21.2 dBi at 37.2 GHz. The 8 × 8, 8 × 16, and 8 × 32 antenna array designs described here were simulated and optimized using CST Microwave Studio, which is a 3D full-wave electromagnetic solver. The overall characteristics of the array in terms of reflection-coefficient and radiation patterns makes the proposed design suitable for mm-Wave 5G and other communication systems.

Bandwidth Improvement of a Cone-Inverted Cylindrical and Cross Hybrids Dielectric Resonator Antennas

This work employs the coaxial probe method to stack and excite two cone-inverted cylindrical and cross-hybrid dielectric resonator antennas at a standard operating resonant frequency of 5.438 GHz. A drawback of these standard Dielectric Resonator Antennas (DRAs) is their narrow bandwidth. For good antenna performance, a stacked DR geometry and a thick dielectric substrate with a low dielectric constant are desired since this provides large bandwidth, better radiation power, reduces conductor loss and reduces the nonappearance of surface waves. Many approaches, such as changing the shape of the dielectric resonator, have been used to enhance bandwidth. Using DRA, which has the lowest dielectric constant, increases the bandwidth and the electromagnetic energy. In the current work, bandwidth improvement was significantly achieved by the proposed geometry by varying the antenna size. A novel hybrid DRA configuration is used to increase the bandwidth of the antenna to 89.27% and 149.23% due to cone-inverted cylindrical and cross-hybrid dielectric resonator antennas, respectively. The DRA is designed numerically via the Finite Difference Time Domain (FDTD) method. Several parameters like return loss, input impedance (verified at ) and radiation pattern are calculated. Furthermore, the stacked-hybrid technique is used to enhance the antenna's performance, which is useful for broadband communication and the demand for wireless.

The effects of the dielectric substrate thickness and the loss tangent on the absorption spectrum: a comprehensive study considering the resonance type, the ground plane coupling, and the characterization setup

In this study, the effects of dielectric substrate thickness and the dielectric loss tangent on the absorption spectrum are investigated parametrically in S-band. The study has been conducted on two different absorber topologies, one is closed ring resonator (CRR) and the other is composed of a split ring resonator (SRR), to observe the effects on both LC - and dipole-type resonances. The studies on the substrate thickness have been performed both numerically and experimentally, whereas the studies on the dielectric loss tangent have been performed numerically. The results agree with the literature such that the substrate thickness has significant effects on the resonant frequency and the absorption peak level which is explained by the impedance matching phenomenon. Besides, we show that the frequency shift behavior (i.e. redshift or blueshift) in response to substrate thickness change highly depends on the coupling between the resonator structure and the metallic ground plane. Moreover, the responses of absorption spectra to the changes of substrate thickness and dielectric loss are very similar whether it is due to an LC or a dipole-type resonances. We believe that the comprehensive and systematic parametric analyses in whole contributes to the literature especially considering the experimental studies in microwaves.

Design and Analysis of a RFID Reader Microstrip Array antenna for IoT Applications in Smart Cities

This paper presents the design of 2*1 and 4*1 RFID reader microstrip array antenna at 2.4GHz for the Internet of things (IoT) networks which are Zigbee, Bluetooth and WIFI. The proposed antenna is composed of identical circular shapes radiating patches printed in FR4 substrate. The dielectric constant εr and substrate thickness h are 4.4 and 1.6mm, respectively. The 2*1 and 4*1 array antennas present a gain improvement of 27.3% and 61.9%, respectively. The single,2*1 and 4*1 array antennas were performed with CADFEKO.

Method of Moment Analysis of Carbon Nanotubes Embedded in a Lossy Dielectric Slab Using a Multilayer Dyadic Green’s Function

Modeling the electromagnetic response of carbon nanotube (CNT) reinforced composites is inherently a 3-D multiscale problem that is challenging to solve in real time for nondestructive evaluation (NDE) applications. This article presents a fast and accurate full-wave electromagnetic solver based on a multilayer dyadic Green’s function approach. In this approach, we account for the effects of the dielectric slab, where the CNTs are embedded, without explicitly discretizing its interfaces. Due to their large aspect ratios, the CNTs are modeled as arbitrary thin wires (ATWs), and the method-of-moment (MoM) formulation with distributed line impedance is used to solve for their coupled currents. The accuracy of the in-house solver is validated against the commercial MoM and the finite element method (FEM) solvers over a broad range of frequencies (from 1 GHz to 10 THz) and for a wide range of dielectric slab properties. Examples of 100 nm-long vertical and horizontal CNTs embedded in a 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> -thick lossy dielectric substrate are presented. The in-house solver provides more than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50\times $ </tex-math></inline-formula> speed up while solving the vertical CNT and more than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$570\times $ </tex-math></inline-formula> speed up while solving the horizontal CNT than a commercial MoM solver over the GHz-to-THz frequency range.

Optimization Design and Development of UHF Antenna for PD Detection in Substation

In this paper, a directional logarithmic periodic antenna is designed to meet the application requirements of local discharge detection in substation.The model of log-periodic dipole antenna was established by using high frequency electromagnetic wave simulation software, and the effects of dielectric substrate thickness, dielectric constant of dielectric substrate and patch size parameters on antenna return loss and standing wave ratio were analyzed.Finally, the dielectric substrate thickness of the antenna is 1.6mm, the material is TEflon, and the width of the assembly line is 4mm.According to the selected antenna type and size, the uHF signal receiving antenna is manufactured.

Performance analysis of microstrip patch antenna using a four-layered substrate of different materials

Substrates of different materials have a significant role in the design of microstrip patch antennas due to their varying chemical, thermal, and physical properties. The authors of this research study proposed an examination into the performance of multi-band microstrip patch antennas mounted on multi-layered dielectric substrates such as FR-4, GaAs, polyethene, and plexiglass The primary goal of this study is to improve the performance of the proposed microstrip patch antenna in terms of return loss, bandwidth, gain, and power density by adding and stacking four different substrates of different material types with an equal dielectric substrate thickness of 1.8 mm, equal patch dimensions of 37 mm × 52 mm, and equal substrate dimensions of 50 mm × 80 mm. The results reveal that adding and stacking substrates of different material kinds improves the performance of the proposed microstrip patch antenna. Moreover, there is a shift in resonance frequencies as well as a shift in beams, operating as a smart antenna. Further study has been undertaken by loading metamaterial-based split-ring resonators on the proposed patch and the ground plane to improve performance. The proposed antenna is extremely useful for electronic communication systems that employ WLAN/Wi-Fi.

Design and Implementation of Triple Band Half Mode Substrate Integrated Waveguide (HMSIW) Antenna with Compact Size

This study investigated structure strategies and exploratory scenarios for a half mode substrate integrated waveguide (HMSIW) antenna. The proposed antenna consists of three Hilbert cells, which are simulated by using CST programming. The antenna was manufactured with the realities of minor imperfections and high incorporation. The proposed structure offers a suitable substrate integrated waveguide (SIW) with about a decrease in size by half. In addition, Hilbert cells were added to realize the triple-band characteristics with good impedance matching, radiation patterns, and radiation performance. The antenna was fabricated on h = 1 mm thick dielectric substrate with dielectric constant (𝜀𝑟 = 4.3). The Hilbert cells were drilled on the top plane of the antenna substrate and fed using a microstrip transmission line. The proposed antenna is small, with a slot side length of approximately half of the guided wavelength. The three developed Hilbert cell HMSIW antenna resonates at 3.25, 5.94 and 6.5 GHz with a bandwidth of 2.97, 2.25 and 2.29% within a return loss of ‑38.77, ‑35.82 -23.35 dB, respectively. The results showed enhancements in antenna gain of 3.56, 4.97 and 6.43 dBi, with a radiation efficiency of -1.253, -0.493 and -0.586 dB, respectively.

Design and Analysis of a RFID Reader Microstrip Array Antenna for IoT Applications in Smart Cities

This paper presents the design of 2*1 and 4*1 RFID reader microstrip array antenna at 2.4GHz for the Internet of things (IoT) networks which are Zigbee, Bluetooth and WIFI. The proposed antenna is composed of identical circular shapes radiating patches printed in FR4 substrate. The dielectric constant εr and substrate thickness h are 4.4 and 1.6mm, respectively. The 2*1 and 4*1 array antennas present a gain improvement of 27.3% and 61.9%, respectively. The single,2*1 and 4*1 array antennas were performed with CADFEKO.

Compact dual-band millimeter-wave antenna for 5G WLAN

Abstract This paper presents a novel compact dual-band printed antenna with an omnidirectional radiation pattern for 5G WLAN. The antenna element comprises a star-shaped patch with six disc-shaped elements at the top and a defected ground structure at the bottom, having a radius of 3.77 mm for both. The proper feeding point and alignment with its element parameters help to achieve good impedance matching. The proposed antenna has a single center feed, a low profile, and a straightforward compact structure without any feeding complexity. A high reception fidelity antenna with comparable bandwidth and moderate gain is presented. The prototype radiator was printed on a 4 mm radius and a 1.6 mm thick dielectric substrate (Rogers RT/Duroid 5880), with a dielectric constant of 2.2. The designed antenna is fabricated and measured to validate the simulation result. The measured impedance bandwidth of 1.3 GHz (27.5–28.8 GHz) and 2.2 GHz (32.45–34.65 GHz) with a respective measured gain of 1.1 and 3.2 dBi are achieved at 28 and 34 GHz. The simulated radiation efficiency of above 95% is achieved for both bands. A good agreement between simulated and measured results of the proposed work shows that the proposed antenna is suitable for 5G short-range WLAN communications.

Optimization and Analysis of Multilayer Planar Spiral Coils for the Application of Magnetic Resonance Wireless Power Transfer to Wearable Devices

In this study, small multilayer planar spiral coils were analyzed and optimized to wirelessly charge an in-ear wearable bio-signal monitoring device in a wine-glass-shaped transmitter (Tx) based on magnetic resonance wireless power transfer (MR-WPT). For analysis of these coils, a volume filament model (VFM) was used, and an equivalent circuit formulation for the VFM was proposed. The proposed method was applied to design effective multilayer coils with a diameter and height of 6 and 3.8 mm, respectively, in the wearable device. For the coils, a printed circuit board having a 0.6 mm thick dielectric substrate and a 2 oz thick copper metal was used. Moreover, the coils on each layer were connected in series. The dimensions of the double-, four-, and eight-layer coils were optimized for the maximum quality factor (Q-factor) and coupling efficiency. The operating frequency was 6.78 MHz. The optimal dimensions for the maximum Q-factor varied depending on the number of coil layers, pattern width, and turn number. For verification, the designed coils were fabricated and measured. For the four-layer coil, the coupling efficiency and Q-factor using the measured resistance and mutual inductance were 58.1% and 32.19, respectively. Calculations showed that the maximum Q-factor for the four-layer coil was 40.8 and the maximum coupling efficiency was 60.1%. The calculations and measurement were in good agreement. Finally, the entire system of the in-ear wearable bio-signal monitoring device, comprising a wine-glass-shaped transmitter, the designed receiving coil, and a monitoring circuit, was fabricated. The measured dc-dc efficiency of the MR-WPT system was 16.08%.

Special beamforming by means of a semi-spherical Lüneburg lens

The paper considers a semi-spherical Lüneburg lens with a conductive shield. In certain conditions a lens of such design may form radiation patterns without the side lobe or cosecant-type patterns. Such radiation patterns can be formed by controlling the following parameters: antenna feed angle, conductive shield diameter, dielectric substrate thickness. The paper focuses on particular cases of obtaining special-type radiation patterns.

Miniaturized dual stop band frequency selective surface with broadband linear co to cross polarization conversion ability

This work presents a miniaturized angularly stable frequency selective surface (FSS) on a single layer substrate. Unit cell comprises of convoluted circular rings connected cross dipole and linear arrow headed dipole printed on both sides of the substrate. A closely spaced dual stop band resonances are obtained at 10 and 14.3 GHz with frequency ratio of 1.43. FSS shows a − 10 dB stopband bandwidth (BW) from 7.32 to 11.05 GHz (40.61%) and 12.68 to 15.97 GHz (22.97%) with >30 dB stop band rejection at center frequencies. FSS poses the features of stable performance under change in polarization and angularly stable response up to 60° incident angle. Later the proposed FSS is printed on grounded thick dielectric substrate and it shows broadband reflection type co to cross polarization conversion from 7.2 to 17.32 GHz (82.54%) with polarization conversion ratio >80% and oblique angle stability up to 35°. To the best of authors' knowledge, this is the first time in literature a single unit cell geometry with two different properties, spatial filtering on transmission and polarization conversion on reflection have been designed and analyzed in details. A finite array with size 25 × 25 of the proposed FSS is fabricated and the measured filter response shows a good agreement with simulated performance at normal and oblique incidences. The proposed FSS is used as a reflector of a dual band monopole antenna and the simulation results shows gain improvement of 5.51 and 3.8 dB at the two stopband frequencies.

Planar Vertically Polarized Unidirectional Dielectric Radiator Fabry–Perot Antenna Fed by Embedded Thin Slotted Substrate Integrated Waveguide

This work devises and investigates a Fabry–Perot-styled planar unidirectional dielectric radiator (UDR) antenna fed by a thin embedded slotted substrate integrated waveguide (SIW). The proposed UDR-SIW antenna consists of two identical dielectric substrates and an embedded feeding SIW between the two dielectric substrates. This diligently mingled multilayer structure makes it possible to not only use the thick dielectric substrates to narrow down the E-plane pattern for symmetrical radiation but also facilitate its integration with RF subsystems through the thin embedded feeding SIW, thereby achieving a compact size and an effective excitation. An experimental prototype of the URD-SIW antenna is simulated, fabricated, and measured. It features a size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.96\lambda _{0}\,^\ast \,0.65\lambda _{0}\,^\ast \,0.33\lambda _{0}$ </tex-math></inline-formula> and a nearly symmetrical endfire radiation pattern. The antenna presents a measured impedance bandwidth of 9.4% from 26.3 to 28.9 GHz, a gain varied from 8.2 to 10.3 dBi, which is over 10 dBi from 27.7 to 28.4 GHz, and a front to back ratio over 20 dB from 27.5 to 29 GHz. The proposed UDR-SIW antenna has vertically polarized radiation pattern that is different from a conventional UDR antenna; thus, it is an appropriate candidate to replace the SIW H-plane horn in certain applications.

Terahertz spoof surface plasmon sensing based on dielectric metagrating coupling

We propose a terahertz surface plasmon resonance sensor based on dielectric metagrating coupling to the spoof surface plasmon (SSP) mode on periodically grooved metal films. The well-designed silicon metagrating converts the normal incident to the necessary angle in the dielectric substrate exciting SSP with the transmission coupling between couplers and SSP metasurfaces. Using an all-dielectric metagrating as an external coupler, the tightly confined SSP mode can be excited within a small resonant cavity, causing the strong light–matter interaction. The proposed SSP dielectric meta-couplers will pave new routes for ultra-thin and compact sensing devices. The dielectric substrate thickness, the air gap distance between the substrate and the metal groove array, and metal groove gaps have remarkable influences on the characteristics of SSP sensing. The SSP sensing by metagrating coupling with the resonance frequency around 0.404 THz provides a high sensitivity of up to 335 GHz/RIU and a detection limit less than 0.0001 RIU with a frequency resolution of 33.5 MHz. Dielectric metagrating coupling SSP provides enormous potential for constructing ultra-sensitive and compact SSP sensors in the terahertz frequency region.