Rectangular Stub Research Articles

Design of compact patch antenna with enhanced gain and bandwidth for 5G mm‐wave applications

A super compact parasitic patch loaded patch antenna with enhanced gain and super wide band is proposed in this study for 5G millimetre-wave (mm-wave) applications. The proposed antenna has hybrid geometry and is constructed using circular and two rectangular driven patches with two semi-circular parasitic patches fed by stepped impedance microstrip line. The two rectangular stubs are incorporated on driven patch to improve the voltage standing wave ratio (VSWR) bandwidth. The two semi-circular parasitic patches are added on the fundamental radiator (driven/main patch) to further enhance the bandwidth to cover the entire Ka-band spectrum for 5G mm-wave requirements and covers 24–40 GHz frequency spectrum with VSWR ≤2. This designed radiator is feasible to be placed inside the multilayered housing systems or can be integrated along with the electronic components existing on the printed circuit board. Furthermore, a four-element modified corporate feed array configuration is constructed and their enhanced gain performances are compared with proposed radiator (single element). Both the prototypes are fabricated and experimentally validated for impedance and radiation characteristics and it is observed that, the simulated and measured responses are in good arrangement. The presented radiating element finds its applications in future 5G mm-wave, 5G base station controlling networks and 5G wideband code division multiple access.

Development of “ H‐Shaped ” monopole antenna for IEEE 802.11a and HIPERLAN 2 applications in the laptop computer

A very low profile and ultra-thin “H-Shaped” antenna for IEEE 802.11a and HIPERLAN 2 wireless applications in the laptop computer is developed. The antenna is designed using only a pure copper strip of size 17.5(L) × 4(W) mm2 with thickness of only 0.035 mm. The novelty of the proposed antenna is that the antenna is designed with only one rectangular radiating strip without using any additional reactive components, vias or three dimensional structure. Furthermore, the proposed antenna does not require any additional ground plane for installing in laptops. The proposed antenna is comprised of one radiating strip, one rectangular stub, and two resonating slots, namely, “X” and “Y” of length 7.5 mm and 7 mm, respectively. The proposed structure resonates at around 5.5 GHz can cover the (5.15-5.35/5.725-5.825) GHz IEEE 802.11a and (5.15-5.35/5.470-5.725/5.725-5.925) GHz HIPERLAN 2 bands. The fabricated prototype antenna has measured impedance bandwidth (VSWR<2) of 15% (5.10-5.92 GHz) across the operating bands. The measured radiation patterns are nearly omnidirectional along with stable gain of 5 dBi. Moreover, the proposed antenna exhibits excellent radiation efficiency of around 90% across the operating bands. The simulated and measured results of antenna are found to be in good agreement. The very low profile and ultra-thin structure make it an excellent candidate for wireless operations in the ultra-thin laptop computers.

矩形钢管混凝土轴压短柱极限承载力的计算

矩形钢管混凝土轴压短柱极限承载力的计算

A quintuple mode resonator based bandpass filter for ultra-wideband applications

This paper presents a new configuration of quintuple mode resonator for designing a bandpass filter for ultra-wideband applications. The multiple-mode resonator is constituted by two capacitive ended rectangular stubs and connected with a high impedance microstrip line. Inter-digital coupled feed lines are designed to excite the resonator. Standard analytical approach based on odd-/even-mode analysis is applied to examine the resonant characteristics of the multi-mode resonator. The proposed filter has the characteristics of low insertion loss, wide stopband along with compact size. The bandwidth (|S11| ≤ − 10 dB) of the proposed filter has been observed to vary from 3.11 to 10.63 GHz with low insertion loss value uniform around − 0.8 dB. A wide stopband with attenuation of more than 15 dB (11.27–20 GHz) is observed for the proposed design. The filter occupies a compact area equal to 23.4 mm × 10 mm (about 0.43λg × 0.09λg, where λg is the guided wavelength at 6.85 GHz). The simulated results agree well with the measured results validating the effectiveness of the work.

Arc-Shaped Strip in Radiating Patch with Rectangular Stubbed Ground Plane for Wideband Applications

A printed planar antenna having compact dimensions of 0.35×0.25λ, mm2 and fed by a microstrip line for wideband applications is presented. The proposed antenna consists of a radiating patch, a new arc-shaped strip, microstrip feed line, and a rectangular stub loaded ground plane. Furthermore, the ground plane of the fundamental radiator is modified to improve the voltage standing wave ratio (VSWR) bandwidth. A rectangular stub is added inside the ground plane to provide the bandwidth to suit the modern automotive requirements. We have analyzed the proposed antenna in terms of VSWR, reflection loss, gain, radiation pattern, and the housing effect. The measured results indicate that the antenna achieves a wide useable fractional bandwidth ratio of 129% at VSWR ≤ 2, ranging from 4.8 to 21.7 GHz. A measured bandwidth of 119% at VSWR ≤ 1.5 (5.5–20.9 GHz) is obtained. Stable quasi-omnidirectional radiation patterns with an acceptable gain of 4.87 dBi are achieved.

A Broadband P-Shaped Circularly Polarized Monopole Antenna With a Single Parasitic Strip

A new broadband circular polarization (CP) monopole antenna with simple structure is proposed. The antenna consists of a P-shaped monopole and modified ground plane with rectangular stub, and results demonstrated that the 10 dB impedance bandwidth (ZBW) is 118.5% (1.6-6.25 GHz) and the 3 dB axial-ratio bandwidth (ARBW) is 104.4% (1.9-6.05 GHz). Procedures to improve the proposed antenna design and the CP mechanism analysis were performed. The performance of different parameters is presented. The advantages of the proposed antenna are broader ZBW and ARBW, simpler structure, and compact size.

A Compact Rectangular Microstrip Patch Antenna Loaded with Stubs and Defected Partial Ground Structure for UWB Systems

This paper presents the prototype and simulations of a compact rectangular microstrip patch antenna for ultra-wideband applications. The proposed antenna is printed on FR4 (Flame Retardant) substrate with relative permittivity of 4.4, dielectric loss tangent of 0.0024 and the dimensions of 57 × 25 × 1.57 mm3 . The radiating patch of the antenna is loaded with two rectangular stubs along its upper and lower edges and an equilateral triangular notch is truncated from the reduced ground plane to achieve optimum results in terms of bandwidth and reflection coefficient. It is fed along the centerline of symmetry by 50Ω microstrip feed line. The simulated return loss ( ) characteristics show that the proposed antenna has a capability of covering the wireless bands from 0.17GHz to 7.25GHz with impedance bandwidth of 7.08GHz and exhibits a peak gain of 5dB at 7.25GHz which is acceptable for UWB systems.

Ultra-thin flexible fractal antenna for 2.45 GHz application with wideband harmonic rejection

This paper presents, the design, and characterization of a coplanar waveguide (CPW) fed ultra-thin, low-profile, and flexible fractal antenna with a wideband harmonic rejection for 2.45-GHz ISM band spectrum applications. The antenna consists of rectangular fractal patches and a stub, etched on a very thin substrate. The fractal patch is utilized to achieve miniaturization of 30% with respect to conventional quadrilateral patch antenna. A rectangular stub is introduced perpendicular to the feedline to minimize the harmonics over a wide frequency band 3.3–11.0 GHz. Simulated and measured results demonstrate that the antenna offers an operating band 2.276–2.72 GHz, which fully covers the ISM band (2.4–2.5 GHz). Along with this, the antenna exhibits promising radiation characteristics of omnidirectional gain around 2.2 dBi and radiation efficiency of better than 95%. The proposed antenna has a compact overall size of 0.24λo × 0.20λo × 0.0005λo (λo is the free-space wavelength at 2.45 GHz) along with other advantages, including ultra-thin geometry and wide harmonic rejection. These features make the proposed antenna become a potential candidate for ISM band applications.

A CPW-fed compact monopole antenna with defected ground structure and modified parasitic hilbert strip having wideband circular polarization

A novel CPW-fed monopole antenna with wideband circular polarization is proposed. The antenna consists of a basic rectangular monopole, fed by a 50 Ω microstrip line, through partial asymmetric impedance steps to attain wideband characteristics. On either side of the feed line, there are sections of partial, asymmetric ground planes. The ground plane on the left is appended with a rectangular stub and a step notch. Wideband circular polarization is achieved by using a strip around the upper end of the monopole and also by a parasitic modified Hilbert strip to the right of the monopole. The monopole, the upper parasitic strip and the modified parasitic Hilbert strip are coupled together by proximity coupling yielding the wide bandwidth. The antenna has been fabricated and the simulated and measured results were compared. The antenna has an impedance bandwidth ranging from 2.04 GHz to 7.95 GHz (118.2%) and an axial ratio bandwidth ranging from 3.6 GHz to 6.84 GHz (62%), thus covering the Wireless Local Area Network (WLAN) 5.2/5.8 GHz, the Worldwide interoperability for Microwave Access (WiMAX) 3.5/5.5 GHz and also partially covering the C-band (4–8 GHz). The antenna shows good radiation characteristics and obtains a reasonable gain over the entire operating frequency band.

A Compact Dual-Band Stacked Patch Antenna With Dual Circular Polarizations for BeiDou Navigation Satellite Systems

A compact dual-band and dual-circular polarization (CP) stacked patch antenna is investigated for BeiDou navigation satellite system. The proposed antenna employs a single coaxial probe to feed two layers of patches simultaneously, realizing dual-band operation. The bottom patch with symmetrical slant corner-cuts and the top one with two rectangular stubs on the diagonal produce a pair of degenerated modes, achieving CP radiation. Furthermore, two L-shaped stubs are loaded on the top patch to widen impedance bandwidth. A prototype operating at the bands of 1.615/2.492 GHz was fabricated and measured. Both the left- and right-handed CP radiations are obtained concurrently in the dual bands. The proposed antenna has a profile of 4.6 mm $({{{\bf 0}}.{{\bf 024}}{{{\bf \lambda }}_0}})$ and occupies an area of $\text{70}\;{\text{mm}} \times \text{70}\;{\text{mm}}\;({0.38{\lambda _0} \times 0.38{\lambda _0}})$ . The measured impedance bandwidth with | S 11| < –10 dB is 9.1% and 5.1% for the lower and upper bands, respectively. The measured 3 dB axial-ratio bandwidth is more than 1% for both bands.

A compact coaxial fed metamaterial antenna for wireless applications

A novel planar metamaterial based dual band antenna for WLAN and WIMAX application is reported. The antenna consists of two metamaterial structures (i.e. Square Complementary Split Ring Resonator (SCSRR) and circular Split Ring Resonator (SRR)) and a rectangular stub as the radiating part. The specialty of the proposed metamaterial structure is that each metamaterial unit cell independently controls a particular band. The extraction of medium parameters through waveguide set-up is elaborated in detail. The antenna has a very compact dimension of 0.24λ1 × 0.21λ1× 0.03λ1 (20× 18× 2.54 mm3 at a lower frequency of 3.6 GHz, with |S11|<−10 dB bandwidth of about 2.57% (3.42–3.51 GHz) and 6.38% (5.61–5.98 GHz). Stable radiation pattern, good impedance matching and radiation efficiency more than 95% are noticed across the targeted bandwidth of the antenna.

Enhanced Matching and Vialess Decoupling of Nearby Patch Antennas for MIMO System

Simultaneous improvement of matching and isolation for a modified two-element microstrip patch antenna array is proposed. Two simple patch antennas in a linear array structure are designed, whereas the impedance matching and isolation are improved without using any conventional matching networks. The presented low-profile multifunctional vialess structure comprises only two narrow T-shaped stubs connected to feedlines, a narrow rectangular stub between them, and a narrow rectangular slot on the ground plane. This design provides a simple, compact structure with low mutual coupling, low cost, and no adverse effects on the radiation and resonance. To validate the design, a compact, very closely spaced antenna array prototype is fabricated at 5.5 GHz that is suitable for multiple-input–multiple-output systems. The measured and simulated results are in good agreement with 16 and 40 dB of improvements in the matching and isolation, respectively.

A metamaterial hepta‐band antenna for wireless applications with specific absorption rate reduction

Present article embodies the design and analysis of slotted circular shape metamaterial loaded multiband antenna for wireless applications with declination of SAR. The electrical dimension is 0.260 λ × 0.253 λ × 0.0059 λ (35 × 34 × 0.8 mm3) of proposed design, at lower frequency of 2.23 GHz. The antenna consists of circular shape rectangular slot as the radiation element loaded with metamaterial split ring resonator (SRR) and two parallel rectangular stubs, etched rectangular single complementary split-ring resonator (CSRR) and reclined T-shaped slot as ground plane. Antenna achieves hepta bands for wireless standards WLAN (2.4/5.0/5.8 GHz), WiMAX (3.5 GHz), radio frequency identification (RFID) services (3.0 GHz), Upper X band (11.8 GHz—for space communication) and Lower KU band (13.1 GHz—for satellite communication systems operating band). Stable radiation patterns are observed for the operating bands with low cross polarization. The SRR is responsible for creating an additional resonating mode for wireless application as well as provide the declination in SAR about 13.3%. Experimental characteristic of antenna shows close agreement with those obtained by simulation of the proposed antenna.

Combined triple band circularly polarised and compact UWB monopole antenna

A new design of a compact ultra-wide band (UWB) monopole antenna with triple-band, triple-sense circular polarisation (CP) is presented here. It is composed of a compact quad-circular monopole, a fractal parasitic ring resonator, a triangular ring resonator, rectangular ring resonator, and modified `T' and `I' shaped slots on the ground plane along with a rectangular stub with `E'-shaped slot on the right side of the monopole. The proposed antenna radiates left-hand circularly polarised (LHCP) wave at lower and mid-frequency bands, while right-hand circularly polarised (RHCP) wave at upper frequency band. The results show that the antenna covers an ultra-wide bandwidth from 3.1 to 11 GHz (112%). Moreover, the proposed antenna achieves good CP characteristics at Citizens Broadband Radio Services in USA (3.55-3.72 GHz), artificial magnetic conductors and WLAN upper frequency spectrum (4.81-5.61 GHz), VSAT services & Satellite Communication and Ground Surveillance RADAR (9.29-10.95 GHz), respectively. Novelty of this article lies in designing a compact printed UWB monopole antenna with combined triple band CP characteristics controllable by adjusting the antenna design parameters. The simulated and measured results of the antenna have been compared and seen to be in reasonable agreement.

Triple band omnidirectional miniaturized metamaterial inspired antenna using flipped rectangular stub for LTE, WiMAX, and WLAN applications

In this article, a miniaturized metamaterial (MTM) inspired antenna with triple band characteristics is presented for LTE/WLAN/WiMAX applications. The antenna mainly consists of a square shaped split ring resonator (SRR) with rectangular stub connected in the outward direction. Due to inward flipping of the same rectangular stub leads to 20% antenna miniaturization without degrading the resonance behavior. The SRR produces first and second band, while the third band is enhanced due to flipping of inward stub and addition of rectangular type slot in the partial ground plane. The antenna exhibits tri-band characteristics with each bands centered at 2.23, 3.65, and 5.13 GHz, having −10 dB impedance bandwidth of 9.42%, 12.88% and 15.34% for the first, second, and third band, respectively. The antenna has a footprint size as low as 0.16 λ0 × 0.18 λ0 × 0.012 λ0 corresponding to 2.23 GHz with a measured gain of 2.22, 2.31, and 1.98 dBi., and measured radiation efficiency of 70%, 72.75% and 82.57% in the three bands, respectively. The prototype of the antenna is fabricated and simulated results are verified through measurements.

Compact and Broadband Microstrip Band-Stop Filters with Single Rectangular Stubs

In this research, a compact and broadband microstrip line quarter-wavelength open circuited stub, which is the core of the band-stop filter, is studied from the viewpoint of the characteristic impedance ratio between the main transmission line and the stub line. Furthermore, a circuit pattern in which an inductive diaphragm is inserted at the stub attachment point using a stepped impedance structure is examined, and an evaluation of frequency adjustment and miniaturization is investigated. The results are compared with the well-known radial stub. Good agreement was obtained between the measured and simulated values up to 5 GHz. Good stop bandwidth was obtained, and the validity of the proposed method is confirmed. The application to other frequency bands is straightforward. The proposed structure is applicable as an alternative to the existing radial stub used for bias T to prevent the reverse flow of the Radio frequency (RF) signal to direct current (DC) source. It is also applicable for the waveguide E-plane band-stop filter, for preventing unwanted leakage from narrow gaps by substituting to a short-circuited stub with a capacitive window, by using the same approach used in the microstrip line H-plane discontinuity.

Design of Dual-Band Bandpass Filter With Simultaneous Narrow- and Wide-Bandwidth and a Wide Stopband

This paper presents a novel dual-band bandpass filter with narrow and wide passband simultaneously and a wide stopband. The dual-band bandpass filter is implemented using a stepped-impedance ring loaded resonator (SIRLR). The properties of the SIRLR are analyzed in detail based on the even- and odd-mode equivalent circuits. Resonant modes, excited by SIRLR, can be controlled and used to form a narrow passband at 2.4 GHz with bandwidth ratio of 8% and a wide passband from 3 to 5 GHz, with insertion losses less than 1.5 dB for both two passbands. Three transmission zeros are created near the passband edge to improve the passband selectivity and achieve a sharp cutoff skirt (over 60 dB/GHz). In addition, for wide stopband consideration, rectangular stub loaded resonators (RSLRs) are tapped on the input and output ports of above dual-band filter without destroying the dual-band performances. Thus, the proposed dual-band filter with a wide stopband region from 5 to 20 GHz with a rejection level of 25 dB is also achieved. The measured results show a good agreement with the simulated results.

Compact ultra‐wideband microstrip antenna with dual polarisation/multi‐notch characteristics

A set of two compact ultra-wideband (UWB) antennas are presented and investigated in this study. Antenna 1 is a dual-polarised antenna consisting of a hexagonal wide slot, hexagonal stub and rectangular stub in the ground plane for getting UWB radiation characteristics and wide axial-ratio bandwidth. Antenna 1 radiates for 3.1-10.8 GHz band with 3-dB ARBW of 67.76% (4-8.1 GHz). Antenna 2 is a multi-notch UWB antenna and is designed by protruding out a rectangular spiral stub in the ground plane of antenna 1. It has been demonstrated in this work that a desirable number of band elimination notches (up to 14) can be easily achieved in antenna 2. Antenna 2 has been successfully fabricated and experimentally verified for seven band elimination notches with simulated and calculated band elimination notch frequencies in good agreement with each other.

Broadband circularly polarized slot antenna arrays using linked elliptical slots forC- andX-band applications

Compact broadband circularly polarized elliptical slot antenna arrays (CPESAAs) are devised based on 2 × 2 and 4 × 4 circularly polarized (CP) elliptical slot antennas and a sequential phase feed network. To realize the circular polarization, eight rectangular stubs are embedded in the feed structure to excite two orthogonal E vectors in 2 × 2 CPESAA configuration. Moreover, by taking four rectangular slots out from each array element, return loss and axial-ratio bandwidths are noticeably increased. The investigated simple array element has a compact size of 20 × 20 × 1 mm3. As well, 2 × 2 CPESAA occupies a compact size of 55 × 60 × 1 mm3, which operates within the frequency band 4.18–9.35 GHz. Thus, 76.4% of S11&lt; −10 dB and 51.4% of CP bandwidth (4.43–7.5 GHz) are covered. Moreover, proposed 4 × 4 CPESAA is printed on 110 × 110 × 1 mm3FR4 substrate and covers the frequency band of 1.15–12.98 GHz with CP at 2.95–8.82 GHz. Throughout the study, the design process of the proposed antenna arrays are presented and discussed in detail.

Printed dipole antenna and its arrays for wireless applications

This paper proposes single element of micro-stripe antenna having wider bandwidth and also its arrays which are implemented for wire-less applications. In contemplation of wide frequency range of operation, antenna is fed with integrated balun. The single element antenna works under frequency range of 34GHz to 46GHz where reflection loss is less than -10dB and the obtained gain is 2.1 dBi. The linear 8-element array of antenna has been implemented and to obtain low mutual coupling between the elements of antenna a rectangular stub has been implemented. By enforcing the array methodology the not only the overall gain of the antenna has increased but also results in wider scanning angle.