Slot Etching Research Articles

Broadband low radar cross section frequency selective surface radome based on phase cancellation and spatial filtering

AbstractThis letter introduces a novel design approach for broadband radar cross section (RCS) reduction of frequency selective surface (FSS) radomes. The approach integrates the principles of phase cancellation and spatial filtering together through a hybrid design method. The phase cancellation is obtained through the checkerboard arrangement of units, and the spatial filtering characteristics is achieved by the slot etched on the ground plane. Experimental and simulation results demonstrate that etching slots on the ground plane maintains broadband in‐phase reflection and bandpass characteristics, thereby extending the bandwidth of RCS reduction through a combination of two operation bands. Theoretical analysis of the working mechanism is also provided using equivalent circuit models. In comparison to the conventional radomes, the proposed FSS radome achieves significant bandwidth improvement for RCS reduction, indicating that it has promising prospects in future low‐RCS radome applications.

WITHDRAWN: A Novel Wideband Circular Polarized Filtering Antenna based on Left Hand Metamaterial

Across a broad frequency range, this reconfigurable antenna can be used for 5G, multi-function radars and automobile applications. To obtain ultra-wideband (UWB), the monopole antenna patch is suitably etched, and a stub is inserted to the feed line. In the meantime, an electromagnetic band gap (EBG) and rectangle slots are added in the partial ground to expand its operational bandwidth, which ranges from 2.7GHz to 23GHz. Size shrinkage rises to 65% when step feed is used in conjunction with partial grinding. Loading left-hand metamaterial (LHM) behind the monopole patch and etching slots at the corners of the rectangular patch results in circular polarization and an increase in gain. By placing a filter across the feedline, the recommended antenna's frequency and bandwidth can be adjusted as needed, enabling bandwidth reconfiguration. The via loaded in the patch extends the axial ratio (AR) bandwidth from 5GHz to 21GHz.The recommended antenna's step feed has a vertical slit that improves impedance matching over a wide operating spectrum.

A compact and narrow-band bandpass filter based on substrate integrated waveguide and spoof surface plasmon polaritons for millimeter-wave applications

This paper presents bandpass filter (BPF) comprising substrate integrated waveguide (SIW) and spoof surface plasmon polaritons (SSPPs), achieving miniaturized size, low insertion loss in the millimeter-wave band. SIW with single-slotted SSPP structure is employing to obtain the transmission zero (TZ) at the low-frequency part, and by introducing the SIW with rhombic periodic walls to enhance the low-frequency rejection. The target passband and TZ of the high-frequency part are realized by increasing the number of etching slots. Furthermore, we innovatively incorporate nonradiative (NR) slots etched below the SSPP structure to gain high out-of-band rejection level. SIW with rhombic periodic walls and slotted SSPP structure as one unit cell is analyzed and demonstrated. Ultimately, the two SIW unit cells are cascaded together to get better out-of-band rejection characteristics and serve as our final design. To validate the proposed design, the BPF prototype is fabricated and measured, showing good electrical performance in terms of high selectivity, low loss, and compact size.

High Gain Metamaterial Implemented Antenna Design with Circular Polarization for mm-Wave 5G and 6G Sub-THz Communication

A high-gain metamaterial-enabled circularly polarized antenna has been proposed. Two patch structures patch A and patch B have been designed by using different shape slots. After slot etching on the patch, two different metamaterial techniques were used. Circular metamaterial (MTM) was implemented for Patch A, while rectangular MTM was used for Patch B. The implementation of MTM resulted in increased antenna gain, as well as improvements in impedance bandwidth RL and AR. So, in the proposed article two antenna structures ANT-A and ANT-B, are presented. The maximum gain achieved for ANT-A is 34.759dBi, covering the frequency bands (28.997-202.113) GHz, and (205.884-336.693) while in the case of ANT-B, it is 36.3155dBi, covering the frequency bands (29.178-330.490) GHz, and (334.936-336.702) GHz. The proposed antenna structure is a useful design for mm-wave 5G and 6G Sub-THz communications.

High gain compact wearable antenna for IoT applications

In this paper, the design of a Defected Ground Structure (DGS)-based microstrip patch antenna tailored for sub-6 GHz 5G applications is reported. The proposed patch antenna is crafted using Jeans textile material. By integrating DGS into the traditional patch antenna design, we achieve a significant reduction in size while simultaneously enhancing the antenna’s performance. The antenna features a rectangular patch shape and is powered through a 50-ohm microstrip feed line. Boasting a compact size of 35.6 × 42.6 × 1.6 mm³, the antenna’s performance is further improved by incorporating DGS and etching slots on the patch. The expertly designed antenna yields a 34.87 dB return loss and a gain of 10.9 dB at a frequency of 3.5 GHz. The fabricated antenna demonstrates a robust impedance bandwidth within the range of 3.41–3.606 GHz. Consequently, the proposed antenna is well-suited for applications in WiMAX and IoT technologies.

A novel compact broadband and radiation efficient antenna design for medical IoT healthcare system.

This paper investigates and develops a novel compact broadband and radiation efficient antenna design for the medical internet of things (M-IoT) healthcare system. The proposed antenna comprises of an umbrella-shaped metallic ground plane (UsMGP) and an improved radiator. A hybrid approach is employed to obtain the optimal results of antenna. The proposed solution is primarily based on the utilization of etching slots and a loaded stub on the ground plane and rectangular patch. The antenna consists of a simple rectangular patch, a 50 Ƹ microstrip feed line, and a portion of the ground plane printed on a relatively inexpensive flame retardant material (FR4) thick substrate with an overall compact dimension of 22 × 28 × 1.5 mm3. The proposed antenna offers compact, broadband and radiation efficient features. The antenna is carefully designed by employing the approximate calculation formulae extracted from the transmission line model. Besides, the parameters study of important variables involved in the antenna design and its influence on impedance matching performance are analyzed. The antenna shows high performance, including impedance bandwidth of 7.76 GHz with a range of 3.65Ƀ11.41 GHz results in 103% wider relative bandwidth at 10 dB return loss, 82% optimal radiation efficiency in the operating band, reasonable gain performance, stable monopole-shaped radiation patterns and strong current distribution across the antenna lattice. The suggested antenna is manufactured, and simulation experiments evaluate its performance. The findings indicate that the antenna is well suited for medical IoT healthcare systems applications.

Etched circular waveguide-based on-chip silicon mode-order converters

Mode-order converters act as the vital higher-order mode sources for on-chip multimode applications. Here, we propose a silicon-based mode-order conversion scheme by leveraging etching slots on the circular waveguide. Through designing and optimizing the etching slots and circular waveguide, the mode-order conversion from input TE0 mode to output TE1 mode has been achieved with the mode conversion efficiency of 99.1%, modal crosstalk of -25.7dB, and insertion loss of 0.21 dB, respectively, in a mode conversion size of ∼8µm×8µm (TE0-TE1). For the device fabrication, only one-step lithography and etching processes will be required, and the requirements of slot width (600 nm) and slot gap (1.49 µm) would be very beneficial for the device fabrication. Moreover, the proposed device scheme can also help achieve other higher-order mode conversions, such TE0-TE2 and TE0-TE3, where their structural parameters and performances are also analyzed. With these features of relatively good device performance, compact size, easy fabrication, and functional scalability, we believe the proposed scheme would be applied in the on-chip multimode applications to enhance their transmission capacities.

Design of compact microstrip bandpass filter using square DMS slots for Wi-Fi and bluetooth applications

This paper presents the design of a compact bandpass filter based on two identical rectangular resonators and is implemented on microstrip technology for Wi-Fi and bluetoothapplications. To reduce the size of the filter, the defected microstrip structure (DMS) technique is proposed. This technique consists of etching slots in the rectangular resonator, which results in a change in the line properties and increase of the effective inductance and capacitance. This feature is used for miniaturization. The designed filter has a compact size (6.82x8.3) mm² with a low insertion loss of -0.1 dB and a good return loss of -36 dB. The simulation results are realized using the (computer simulation technology) CST Microwave software.

Design of wide band slotted microstrip patch antenna with defective ground structure for ku band

This paper proposes a microstrip patch antenna (MSPA) in the Ku band for satellite applications. The antenna is small in size with dimensions of about 40 mm×48 mm×1.59 mm and is fed with a coaxial cable of 50 Ω impedance. The proposed antenna has a wide bandwidth of 3.03 GHz ranging from 12.8 GHz to 15.8 GHz. To realize the characteristics of wideband the techniques of defective ground structure (DGS) and etching slots on the radiating element are adopted. The antenna is modeled on the FR4 substrate. A basic circular patch is selected for the design of a dual-frequency operation and in the next step DGS is introduced into the basic antenna and enhanced bandwidth is achieved at both the frequencies. To attain wider bandwidth two slots are etched on the radiating element of which one is a square ring slot and the second one is a circular ring slot. The novelty of the proposed antenna is a miniaturized design and unique response within the Ku band region which is applicable for wireless UWB applications with VSWR <2 and an average gain of 3.6 dB.

Design and experimental verification of compact dual‐element quasi‐self‐complementary ultra‐wideband multiple‐input multiple‐output antenna for wireless applications

AbstractIn this article, a compact dual‐element quasi‐self‐complementary (QSC) multiple‐input multiple‐output (MIMO) antenna for ultra‐wideband (UWB) communication is presented. The overall area of the antenna is 32 × 39 mm2 (0.26 λl × 0.31 λl, where, λl is at lowest cutoff frequency) which is designed on low cost FR‐4 substrate. It has two half‐cut flower shaped (HCFS) radiators on its top which is formed by merging four ellipses of same eccentricity and then splitted in two halves at the center. On the other side, quasi‐self‐complementary phenomenon is introduced via etching slots which are complement to the radiator's shape. Also, a rectangular slit on the ground plane just below the feed line improves impedance matching. The proposed antenna operates in the range of frequencies 2.43GHz to 11.2GHz with high inter‐port isolation of greater than ‐19 dB over entire frequency of interest. Moreover, the stability of the design is validated in terms of diversity parameters [envelop correlation coefficients (ECC), channel capacity loss (CCL), mean effective gain (MEG), and Effective diversity gain (EDG)] and radiation parameters which makes it suitable for UWB‐MIMO wireless application.

Analysis of 8.71 GHz operated gold nanoparticles based multi-slotted patch antenna etched on epoxy dielectric material having broadsided radiation characteristics

This paper deals with the design and study of multi-slot patch antennas etched on a epoxy dielectric material coated with gold nanoparticles suitable for wireless system based applications. The antenna is uniformly coated with gold nanoparticles which tends have better conductivity compared to copper; the coating is done using sputtering process. In addition, the characteristics parameters of antenna etched on glass epoxy dielectric material are studied and they are return loss (RL), reflection co-efficient, 2D patterns, half power beamwdith (HPBW) and VSWR with conclusions are considered. The proposed antenna multi-slot epoxy substrate patch antenna1 (MSEPA 1) attained bandwidth (BW) of 2210 MHz (-37 dB of RL). A decent gain of 8.29 dB with VSWR less than 1.5 is obtained as the improving feature for the designed MSEPA1 through the experimental process. The dimensions of patch having length, width are kept constant as a factor of wavelength (λ). Desired antenna resonance with wide band characteristics is seen because of etching slots and gold nanoparticles deposition on dielectric material. Simulation is performed using electromagnetic simulation software MG IE3D V.15.3.

A Compact Triple Band Antenna for Military Satellite Communication, Radar and Fifth Generation Applications

A compact triple band antenna by using etching slots technique in the radiation element is presented in this paper. The proposed antenna is designed to target three different frequencies: 7.5 GHz (military satellite communication), 9 GHz (radar applications) and 28 GHz (fifth generation applications). The fabricated prototype of the antenna has overall dimensions of 13x12.8x1.6 mm3. Measurements were carried out to validate the simulation results. The impedance bandwidths are 259 MHz (7.435-7.695 MHz), 355 MHz (8.86-9.221 MHz) and 2.67 GHz (26.79-29.433 GHz) with return loss less than -10 dB. Furthermore, the suggested antenna provides a gain of 3.96 dBi, 3.05 dBi and 5.86 dBi at 7.5 GHz, 9 GHz and 28 GHz respectively. Therefore, the results demonstrate that the proposed triple band antenna can be used for military satellite communication, radar applications and is a good candidate for the future 5G applications.

A Compact Flexible Frequency Reconfigurable Antenna for Heterogeneous Applications

This paper presents a compact frequency reconfigurable antenna for flexible devices and conformal surfaces. The antenna consists of a simple easy to fabricate structure consisting of a stub loaded circular radiator, designed on commercially available RT5880 flexible substrate ( $\varepsilon _{\mathrm {r}} = 2.2$ ) with a thickness of 0.254 mm. The combination of stub loading and slot etching techniques are utilized to achieve the advantages of compactness, frequency reconfigurability, wide impedance bandwidth, and stable radiation pattern with structural conformability. The frequency reconfigurability is achieved by employing two p-i-n diodes. Simulated and experimental results showed that the antenna operates in various important commercial bands, such as S-band (2 GHz– 4 GHz), Wi-Max (3.5 GHz and 5.8 GHz), Wi-Fi (3.6 GHz, 5 GHz, and 5.9 GHz), 5G sub-6-GHz (3.5 GHz and 4.4 GHz – 5 GHz), and ITU-band (7.725 GHz – 8.5 GHz) with the additional advantages of structural conformability. Furthermore, the performance comparison of the proposed flexible antenna with the state-of-the-art flexible antennas in terms of compactness, frequency reconfigurability, and number of operating bands demonstrates the novelty of the proposed antenna and its potential application in heterogeneous applications.

A Novel Triple-Band Dipole Antenna for WLAN/WiMAX/LTE Applications

Abstract In this paper, a novel triple-band dipole antenna is presented. The proposed antenna has a very simple structure and is easily designed. The idea of the antenna is based on the traditional wideband bow-tie dipole antenna. Via etching slots on the bow-tie patch, three bent dipoles with different lengths which correspond to different operating frequencies are formed. Hence, the triple-band antenna is generated. Each operating frequency band realizes wideband and can be adjusted almost independently. And the antenna is fed by a 50 Ω microstrip line and a wideband microtrip-to-coplanar-stripline (CPS) transition as a balun. The good performances of the proposed antenna are achieved by a mass of simulations and measurements. The measured results have a good agreement with the simulated ones. The results show that the proposed antenna obtains three bandwidths at 2.38~2.65 GHz (10.7 %), 3.17~4.08 GHz (25.1 %), and 4.75~6.00 GHz (23.2 %) with the reflection coefficient less than −10 dB. In addition, the stable gain and quasi-omnidirectional radiation patterns are obtained in the operating frequency bands. Therefore, the proposed antenna is suitable for WLAN/WiMAX/LTE applications.

Bandwidth enhancement of rectangular microstrip antenna with a rectangular slot by using a novel hybrid optimization method based on the ABC and DE algorithms

AbstractIn this study, the bandwidth of the rectangular microstrip antenna is improved by using a new integrated technique consisting of a novel hybrid optimization algorithm (HOA) and HyperLynx® 3D electromagnetic platform based on the method of moments (MoM). The novel HOA is developed by integrating the powerful mutation and crossover strategies of the differential evolution algorithm with onlooker bee stage of the artificial bee colony algorithm. The main objective of the design is to enhance bandwidth of the rectangular microstrip antenna by the etching rectangular slot on the antenna ground plane. The optimal position and sizes of the slot are determined by using the integrated optimization technique. The simulation and measurement results indicated a high improvement in the bandwidth of the rectangular microstrip antenna over 45% by using the proposed slot etching method on the ground plane. Additionally, in order to evaluate performance of the HOA, eight benchmark functions having multi or unimodal characteristics were used. The experimental results show that the performance of the HOA was better than both artificial bee colony and differential evolution algorithms.

High-efficiency broadband excitation and propagation of second-mode spoof surface plasmon polaritons by a complementary structure.

A complementary structure based on coplanar waveguides (CPWs) with periodical etching slots is proposed to support spoof surface plasmon polaritons (SSPPs). In contrast to the traditional slotline-based complementary SSPP structure, a dispersion curve of the second mode by the proposed structure has a much lower starting point from the origin which exhibits greatly improved operating bandwidth. Moreover, tighter confinements of SSPPs in the region of small wave vectors corresponding to lower frequencies can be predicted from the dispersion analysis, which means enhancement of transmission efficiency. Then a simple and efficient transition structure with tapered CPWs and gradient slots is proposed to realize high-efficiency and broadband excitation of the second mode of SSPPs for the first time, to the best of our knowledge. Based on the proposed structure, a seamless connection between CPWs and the SSPP structure can be achieved. The measured insertion loss and return loss below 6.6GHz is better than -0.86 and -13.62 dB, respectively. Furthermore, it can be seen from the measurement results that a 3dB bandwidth ranges from 0 to 10.57GHz, and the return loss is better than -10 dB from 0 to 8.96GHz. The proposed structure can promote the development of plasmonic integrate circuits and functional devices at microwave frequencies.

Design of a Reader Antenna for UHF RFID

A compact and circular polarized antenna for UHF band RFID handset reader was designed, and realized by cutting slits in the antenna patch and etching slots on the ground. Numerical simulation was performed for the characteristics of the antenna with the software HFSS 13.0.The simulation results show that when the size of antenna patch is 68mm×68mm, -10dB return loss impedance bandwidth is 49MHz,VSWR is less than 2 and the largest gain is -0.61dB for antenna in 907～931MHz. Compared with the traditional reader antenna with the same material of the substrate，the improved antenna has a much higher gain．and the size was reduced by 20% and the max gain is raised -0.11dB.

New dual-mode square patch bandpass filter using CSRR slot-type perturbation

A compact dual-mode microstrip bandpass filter using square-patch resonator and a new perturbation element is designed in this letter. This new slot-type element is composed by a complement split-ring resonator (CSRR) with two pairs of etching slots. The nature of coupling between the degenerate modes is investigated with respect to the perturbation size. By proper arranging the orientations of the CSRRs, new coupling characteristics can be obtained. The proposed dual mode bandpass filters are designed, and simulated. The simulation and measure results of proposed bandpass filter are reasonable.

Slow-wave slot microstrip transmission line and bandpass filter for compact millimetre-wave integrated circuits on bulk complementary metal oxide semiconductor

In this study, a novel on-chip low-loss slow-wave slot (SWS) microstrip transmission line is proposed. Unlike conventional slow-wave structures such as photonic bandgap and ladder microstrip transmission line, which usually deal with either the substrate, ground plane or the signal line separately, the periodic patterns of SWS structures are etched along both the conductive metal strip and the ground plane of the microstrip line. The proposed structure, unlike other slow-wave structures does not require extra drilling through the substrate or complex three-dimensional multi-layer structures, only requires coplanar slot etching. The proposed SWS microstrip demonstrates excellent size reduction with minimal increase in loss. To show the utility of the proposed method, two second-order rectangular open-loop filters with and without implementing the proposed SWS microstrip have been designed with similar bandwidths and fabricated in the millimetre-wave (mm-wave) range on 65-nm bulk complementary metal oxide semiconductor (CMOS). Both simulations and measurements demonstrate that the on-chip filter implemented using the proposed SWS has a 52.7% reduction in size while suffering only an additional 0.5 dB in transmission loss penalty. To the best of authors’ knowledge, this compact filter is the first reported mm-wave filter using slow-wave structure on bulk CMOS.

Incorporation of the stress concentration slots into the flexures for a high-performance microaccelerometer

Presented in this paper is a development of a high-performance piezoresistive microaccelerometer based on the slot etching in the quad flexures for the vibration detection of high speed spindle. The proposed structure consists of a proof mass supported by four thin flexures with slots etched in the middle. Boron diffused piezoresistors located near the stress concentration regions are used for sensing the localized stress resulting from the incorporation of the slots into the flexures. Theoretical analysis and finite element analysis show satisfactory results of an improved sensitivity and favorable natural frequency higher than 10 kHz, conforming to the initial design requirements. The microfabrication techniques are described to prototype the two accelerometer chips, one with slots and the other one without slots. The tested microaccelerometers with 3 V DC power supply show an average sensitivity of 0.424 mV/g normal to the proof mass plane, increased by 60.6% than the ones without slots. An average transverse sensitivity is found to be 9.2 μV/g along X axis and 14.2 μV/g along Y axis, either of which is less than 3.5% of prime-axis sensitivity. Concerning the resonant frequency, dynamic experiment shows about 12.46 kHz and is available for the proposed design with a tiny loss of 3.5% compared with the quad-beam design. When taking the product of sensitivity and natural frequency as judgment criteria, an inspiring increase by 28.6% of the figure of merit is accomplished for the proposed accelerometer. Overall, the findings of this study confirm the feasibility of incorporating slots into the conventional configurations to improve the sensor sensitivity while maintaining a comparatively high natural frequency.