Circular Ground Plane Research Articles

Broadband Circularly Polarized Microstrip Patch Antenna Using Circular Artificial Ground Structure and Meandering Probe

To enhance axial ratio (AR) bandwidth, this research proposes a circularly polarized (CP) single-fed microstrip patch antenna using a circular artificial ground structure (AGS) and meandering probe. To achieve broader AR bandwidth, the circular AGS is populated with rectangular unit cells and partially cut unit cells along the circular contour, while the meandering probe is used to improve the impedance bandwidth. Simulations are performed and results compared with that of conventional rectangular-AGS antenna. The simulation results show that the circular-AGS antenna, given 62 mm circular ground plane, achieves broader impedance (5.12 - 9.00 GHz and 54%), AR (5.21 - 8.27 GHz and 45%) and gain bandwidths (3.85 - 7.00 GHz and 58.06%), in comparison with the rectangular-AGS antenna (4.50 - 7.45 GHz and 49%; 4.52 - 7.42 GHz and 21%; and 4.00 - 6.80 GHz and 51.58% for impedance, AR and gain bandwidths). The circular-AGS antenna is capable of converting linear polarization in the off-axial ratio band into circular polarization. To verify, a circular-AGS antenna prototype is fabricated and experiments undertaken. The experimental impedance, AR and gain bandwidths of the circular-AGS antenna are 47.82% (5.17 - 8.42 GHz), 43.81% (5.24 - 8.17 GHz) and 60.74% (3.75 - 7.00 GHz). The proposed circular-AGS antenna can achieve broader AR bandwidth and is thus ideal for broadband CP applications. The novelty of this research lies in the use of circular AGS to effectively enhance AR bandwidth, as opposed to rectangular AGS which is conventionally used in CP polarizers.

Broadband printed MIMO dipole antenna for 2.4 GHz WLAN applications

Broadband printed dipole antenna with elliptical-arms and integrated balun for multiple-input-multiple-output (MIMO) antennas at 2.4 GHz frequency is designed and presented. The MIMO structure is composed of four symmetrical dipole elements and a circular ground plane. To enhance the isolation between contiguous elements, they are placed in a perpendicular direction. Isolation of parallel dipoles with identical polarization is guaranteed by a suitable distance. Outstanding impedance matching, good isolation, high-gain, and stable directional radiation pattern are advantages of this design. Structural simplicity is achieved by printing dipole arms, balun structure, and the ground plane on FR4 substrates. The proposed MIMO antenna is manufactured and tested in the anechoic chamber. The empirical results have a proper discrepancy with the simulation outcomes.

Cross-finned UWB monopole for wireless applications: Design insight and characterization

A simple yet novel cross-finned geometry of a monopole has been explored to realize a strong contender in the family of ultra-wideband antennas. This promises a consistent monopole like radiation over an ultra-wide impedance bandwidth (127%) with improved radiation characteristics. An extensive study supported by experiments has resulted in a reliable design guideline with a strong physical insight. A cross-finned top loaded structure having individual fin length (L) 11 mm and width (W) 5 mm and fin thickness (t) 0.7 mm, fed by probe pin of height h = 2 mm, is fitted to a circular ground plane of radius (Ga) 15 mm. It has been experimentally demonstrated to operate from 5 to 22.5 GHz with as much as 1–7 dBi peak gain and over the band high co-to cross polarization isolation (26–31 dB). The design is found to exhibit desired transmission and reception characteristics in time domain and is extendable up to 32 GHz to the upper side and 1.5 GHz to the lower side of the microwave band. This commercially viable design should find potential applications in compact and miniaturized wireless transceiver systems.

Metallic Monopole Parasitic Antenna With Circularly Polarized Conical Patterns

In this paper, a new geometry for antenna producing conical patterns with circular polarization is proposed. The symmetrically placed parasitic posts, with different horizontal and vertical segments, around the centrally fed monopole control the circular polarization purity and the angle of maximum gain. The 3-D geometry favors high gain at low elevation angles. A circular ground plane atop a choke ring facilitates easy mounting of a radome and improves gain at lower elevation due to lower backlobe. The all-metal radiator has good mechanical stability and remains impervious to large temperature variations, which is ideal for use in space applications. An application to a Martian transponder at the $X$ -band is also discussed. The measured results of the manufactured antennas show a good agreement with those of the simulated one. Furthermore, the optimization of the antenna design parameters allows the antenna to have high gain and low axial ratio (AR), from high elevation ( $\theta _{max}=35^{\circ }$ ) to low elevation ( $\theta _{max}=70^{\circ }$ ) angles.

A novel low‐cost high‐gain antenna design from cuboids and differential strips

This article proposed a novel broadband high-gain antenna designed by suspended cuboids and differential shorting strips on a circular ground plane. The design structure of the proposed antenna is simple and all its components such as cuboids, strips, and ground plane are fabricated by a copper sheet of thickness 0.5 mm. The proposed antenna has measured −10 dB impedance bandwidth (IBW) 45% (2.35-3.7 GHz) with broadside gain of 10.1 ± 0.4 dBi over IBW. The use of differential strips in inner cuboid improved the cross polarization and enhanced the broadside gain. The measured antenna has low cross polarization is below 25 dB in the broadside direction over IBW. The proposed antenna has 1 dB gain-bandwidth 53% (2.2-3.8 GHz) in the broadside. The antenna has been fabricated and measured; the results show a good agreement with simulated results.

Design of an UWB antenna with two slits for 5G/WLAN‐notched bands

AbstractIn this article, we propose a dual notched‐band antenna with 2 slits for ultra‐wideband (UWB) applications. The antenna consists of a circular ground plane and a patch radiator with having 2 slits and a folding arm. The patch with folding arm is used to achieve UWB band while a V‐shaped and a split ring‐shaped slit are used to eliminate the interference from WLAN and 5G band, respectively. The width and length of the slits are optimized to obtain the necessary band notch characteristics. The prototype of the antenna having a total size of 75 × 10 mm2 is fabricated. Simulated and measured results show that the antenna covers the entire UWB frequency ranging from 2.754 to 14.656 GHz (127%) for VSWR < 2 except at notched bands. Moreover, the antenna successfully notched the WLAN band (5.15‐5.825 GHz) and 5G band (3.4‐3.7 GHz) besides of providing a stable gain and radiation patterns.

Wideband circularly polarized antenna with end shorting vias and inverted L-shaped slots

ABSTRACTIn this paper, we present a new wideband circularly polarized (CP) antenna. It has two parts, the first part is a circular ground plane with curved branches, and the second one is a circular patch with curved branches and inverted L-shaped slots. We could obtain a wideband of impedance and axial ratio (AR) through commending inverted L-shaped slots on the patch and loading end shorting vias at the corresponding ends of the arced branches in the patch and ground plane. The realized antenna has a dimension of 43 × 43 × 3.2 mm3, equals to 0.73λ0 × 0.73λ0 × 0.054λ0 (λ0 is the wavelength at the minimum frequency). The tested results illustrated that the impedance and axial ratio (AR) bandwidth are 26.98% (5.29–6.94 GHz) and 25.33% (5–6.45 GHz), respectively. The results of the actual test are basically adjacent with the simulated one.

Normal Mode Helical Antenna on Small Circular Ground Plane

ABSTRACT In this paper, it has been shown that input impedance matching for the Normal Mode Helical Antenna (NMHA) can be obtained by using a small circular ground plane (radius λ/20) without any external impedance matching network. It also discusses the effect of the finite circular ground plane radius, the radius of wire on the input impedance, resonance frequency, and bandwidth of the NMHA. Further, the effects of different ground plane shapes and cupped shape ground plane bending in upward and downward directions on input impedance matching are presented. A prototype of NMHA has been fabricated to operate around 1.8 GHz and the measured results are in good agreement with the simulated results.

Hybrid Circular Ground Planes for High-Realized-Gain Low-Profile Loop Antennas

A novel hybrid circular ground plane integrated with a loop antenna is presented. The ground plane is composed of two different rings: a ring with periodic gaps and an annular concentric ring. The combination of the two rings into one ground plane improves significantly the radiation performance of the radiating element. The proposed antenna is designed to resonate at 2.9 GHz with a return loss of $-\text{24}$ dB and a realized gain of 10.5 dB. To experimentally verify the simulated results, a prototype was fabricated and measured. The simulations and the measurements are in excellent agreement.

Broadband ESPAR antenna using sleeve wires

A broadband electrically steerable parasitic array radiator (ESPAR) antenna is presented. The proposed broadband ESPAR antenna consists of an active monopole, 12 parasitic sleeve wires, 6 parasitic elements and a ground structure. By introducing the sleeve wires into the ESPAR antenna, the operation bandwidth of the ESPAR antenna is broadened effectively. Six copper wires placed around the circular ground plane constitute the ground skirt of the ESPAR antenna. The ground skirt, with low wind resistance, reduces the elevation angle of the radiation beam. A broadband ESPAR antenna operating at 2.2 GHz is designed and fabricated. From the results, the impedance bandwidth, with a 2 VSWR, can operate from 1.70 to 2.70 GHz, which is wider than a conventional ESPAR antenna. The working band of the proposed ESPAR antenna covers the GSM1800/1900/UMTS, LTE2300/2500, and 2.4G-WLAN bands. The electronic beam steering across a range from 0° to 360° with a step size of 60° is realized and the gain from 6.15 to 7.37 dBi is obtained over the operation band.

Compact First-Order Probe for Spherical Near-Field Antenna Measurements at Low Frequencies

Guidelines for designing compact and lightweight first-order probes for spherical near-field antenna measurements at frequencies below 1 GHz that exploit first-order properties of electrically small self-resonant radiators combined into superdirective endfire arrays are established theoretically, exemplified numerically, and validated experimentally. A prototype of the probe designed to operate at a central frequency of 435 MHz exhibits the impedance bandwidth of 15 MHz with a directivity of more than 9 dBi and parasitic $|\mu |\ne 1$ spherical modes suppressed to at least −42 dB. The probe height is just 343 mm above a 720-mm circular ground plane and weighs about 5 kg.

Design of a Ceramic Patch Antenna for Artillery Projectile Positioning Applications

본 논문에서는 GPS/GLONASS 신호 수신을 위해 포탄 신관에 탑재되는 소형 원편파 패치 안테나를 제안하였다. 제안된 안테나는 모서리가 절단된 슬롯형 세라믹 패치와 작은 원형 접지판으로 구성된다. 충분한 원편파 대역폭을 얻기 위해 패치 중앙의 2곳에 소형 슬롯을 배치하고 안테나의 요구되는 임피던스 대역폭을 얻기 위해 패치의 상부 왼쪽 모서리를 절단하였다. 신관 내부에 설계된 안테나는 높이 6㎜와 직경 36㎜의 공간을 차지한다. 안테나의 최적 설계 및 주요 설계 변수에 따른 영향은 CST사의 Microwave StudioTM 프로그램으로 분석하였다. 제작된 안테나는 플라스틱 폼으로 포팅되어 있는 신관 레이돔 내부에 실장된다. 제작된 안테나는 2.5~4.2㏈ic 이득, 5.1~11.6㏈ 축비 및 1.57~1.62㎓에서 –10㏈이하의 반사계수 특성을 보였다.

A new broadband dual‐layer monoplolar circular patch antenna with slot coupling

ABSTRACTA new center‐fed dual‐layer circular patch antenna is proposed for bandwidth enhancement. The proposed antenna consists of a circular ground plane, a slotted circular patch on the lower layer and a parasitic circular patch on the top layer. The slotted circular patch is fed with a coaxial probe. With the help of the slots introduced to the lower patch, the parasitic patch on the top layer is strongly coupled. With the strong coupling of the two patches, a broadband is obtained. A prototype is fabricated. The measured results show that a wide bandwidth of 25% is obtained. Within the bandwidth, the measured peak gain is in the range of 6.2–8.7 dBi. The antenna produces an omnidirectional pattern in the horizontal plane, similar to that generated by a conventional monopole antenna. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:40–43, 2017

Dos geometrías aplicadas a estructuras de defectos sobre planos de tierra rectangulares y circulares

En este trabajo se compara el rendimiento de una antena de parche rectangular realizada sobre planos de tierra rectangular y circular, respectivamente. Se observa una mayor ganancia para el caso circular pero un menor ancho de banda. La comparación se llevó a cabo también cuando a los planos de tierra se agregaron defectos. Como resultado, se observaron cambios en las ganancias, el parámetro S11 y los anchos de banda.Para la antena rectangular sobre substrato rectangular con Defectos en el Substrato (DGS, por sus siglas en inglés) la principal mejora observada fue sobre el parámetro S11. Para el caso del plano de tierra (o substrato) circular, el ancho de banda muestra un incremento de 113.59% comparado con el caso sin defectos. Las antenas fueron simuladas utilizando el software FEKO.

Split ring loaded monopole antenna

A split ring loaded monopole antenna structure for triple-band operation is proposed in this study. Multi-resonance is achieved by attaching two rings to a monopole on a circular ground plane. The connected rings improve the directivity and support multiband response. The authors present a discussion on the multi-resonance operation and investigate the antenna characteristics by changing the dimensions of the structure. Results of the parametric analysis are used to determine the effect of changing the dimensions of the antenna on the three resonant frequencies and also arrive at empirical design equations. An equivalent circuit of the antenna is proposed and is used to explain multi-resonance behaviour of the antenna. Simulated and measured performances of the proposed antenna are compared and a good agreement is observed between the two.

Compact Circularly Polarized Antenna With Wide 3-dB Axial-Ratio Beamwidth

A compact circularly polarized antenna with wide 3-dB axial-ratio (AR) beamwidth is presented. The two pairs of radiators based on mu-negative transmission lines are applied and each radiator has a capacitor at the center and a pair of vias at both edges of the radiator to induce a zeroth-order resonance mode. The two radiators for x-polarized wave are orthogonally aligned to the other two radiators for y-polarized wave, and the 90 ° phase difference is realized by detuning the resonance frequencies of the corresponding radiators. In particular, a circular ground plane is adopted for the symmetrical radiation pattern and optimized to have the wide 3-dB axial-ratio beamwidth. Also, a dual-ground structure is studied to suppress back radiations caused by the compact ground. The 3-dB AR beamwidth is measured as 175 ° - 190 ° , and the measured gains are observed as 3.8 dBic at θ = 0 ° and 0.5 dBic ( - 0.5 - 1.2 dBic) at θ = 60 ° .

WIDEBAND DUAL-POLARIZED OMNIDIRECTIONAL ANTENNA WITH HIGH ISOLATION FOR INDOOR DAS APPLICATIONS

A low-profile dual-polarized omnidirectional antenna is presented. The antenna is a combination of a vertically-polarized (VP) antenna and a horizontally-polarized (HP) antenna. The VP antenna is composed of a circular ground plane, a cross-shaped metal patch with four shorted legs and a top-loading circular ring. The printed dipoles of the HP antenna are fed through a three-way power divider etched on an FR4 substrate. To maintain stable radiation and reflection characteristics, the HP feed coaxial cable is soldered on one patch of the VP antenna to reduce the parasitic current on the feed cable. The VP antenna covers the frequency bands for GSM/2G/3G/4G LTE, and the HP antenna works in an overlapping frequency bands for 3G and 4G LTE communication systems with high isolation. The VP antenna achieves a wide bandwidth of 108% from 800 MHz to 2700 MHz, and its gains are larger than 2 dBi in 800∼960 MHz band and greater than 4 dBi in 1710∼2700 MHz band, respectively. The HP antenna works in the frequency band from 1700 MHz to 2700 MHz, and its gains are greater than 3 dBi. The proposed dual-polarized antenna is simulated, fabricated and measured. Measured results are in good agreement with the simulated ones.

A compact low profile wideband U-shape antenna with slotted circular ground plane

In this article a compact low profile U-shape patch antenna for high gain and wide bandwidth is presented. By introducing an inverted U-shape slot on the circular ground plane (diameter of 40mm) an adjustable wide impedance bandwidth is achieved. The simulated results are confirmed experimentally. An impedance bandwidth (S11≤−10dB) up to about 100.35% is achieved by individually optimizing its parameters. The proposed antenna exhibits nearly stable radiation pattern with a maximum gain of 3.2dBi. It makes the proposed antenna suitable for in wideband applications.

On radiation of omnidirectional axisymmetric antennas with circular ground planes

Two-term asymptotic expansions of the solution to the key scattering problem for the vector toroidal wave with general form of the azimuthal dependence scattered by a semitransparent disk are obtained. The problem is solved in the Kirchhoff approximation. The obtained asymptotic expansions of the scattering pattern can be used for simulation of radiation of omnidirectional axisymmetric antennas with circular semitransparent ground planes. For a metal disk ground plane, corrections to the edge waves in the approximation of the physical theory of diffraction are obtained. The developed theory is used to obtain asymptotic formulas for the radiation pattern of a loop antenna with ground plane and a monopole. The results of simulation with the use of these formulas are compared to the corresponding numerical results obtained with the finite-element method.

Miniaturized Dual-Band Omnidirectional Antenna for Body Area Network Basestations

Challenges arising from body effect in design of implant and on-body antennas has dominated body area network (BAN) basestation antenna design research. However, design of an efficient basestation antenna in a compact size is also a challenge. This letter presents a miniaturized omnidirectional antenna in two bands of 403.5 MHz for medical implant communication services (MICS) and 2.45 GHz for industrial, scientific, and medical (ISM) applications. The antenna consists of two stacked center-fed circular patch over a circular ground plane. The upper and lower patches resonate in MICS and ISM bands, respectively. Each patch is loaded with two vias for miniaturization. The achieved miniaturization factors are 6.3 and 5.1 for MICS and ISM bands, respectively. Since the TM010-mode is excited, the pattern is omnidirectional with a null in broadside. The measurement results show a good agreement with the simulation in terms of reflection coefficient and radiation pattern.