dBic Gain Research Articles

A Novel Compact GNSS Antenna with Plasma Frequency Selective Surface

In this study, a plasma frequency selective surface (PFSS) was designed with an array of ordinary fluorescent lamps backed by a conducting plate. The proposed PFSS structure was used as a reflector with the spiral two arms Archimedean type Global Navigation Satellite System (GNSS) antenna to reduce the overall size of the antenna system. Characteristics and the performance of the proposed system were presented by using the results of simulations and experiments in the GNSS band. The optimum distance between antenna and PFSS was found to be around 35 mm to achieve a maximum gain in the simulation which is a lower profile than antenna with conventional conductive plate (66 mm at the GNSS center frequency). Experimental results show that the antenna system has mean values of around 6.7 dBiC gain, 1.27 dB axial ratio and less than -10 dB return loss in the range of 1.14 and 1.61 GHz. All these results show that the proposed novel antenna system is suitable for the reception of the GNSS signals with the advantage of its low profile design.

An Antenna Solution for Glacial Environmental Sensor Networks

Antennas used in glacial environmental sensor networks and reported in the last two decades have been reviewed. A link budget framework for designing such antenna systems is presented and used to design an antenna system for deployment at the Thwaites glacier, Antarctica. Design details of two left hand circularly polarized cross dipole antennas, one for englacial sensor probes and the other for supraglacial surface receivers are presented. The probe antenna is a 3D bent cross dipole that fits within a borehole of 8 cm diameter while providing a 1 dBic gain at 433 MHz in ice. The surface receiver antenna is a planar printed antenna providing a gain of 6.1 dBic with a quarter wave reflector. Both antennas provide 3 dB beamwidths of at least 50° in the xz and yz vertical planes catering for transmitter-receiver antenna misalignments caused by extended deployments. The antennas displayed good circular polarization and polarization purity traits. The 3 dB axial ratio bandwidths of both the antennas remained 54.9 %. The total efficiencies of the bent cross dipole and the surface receiver antennas were noted as 69.7 % and 86.9 % respectively. Lastly, the 433 MHz band has been validated for achieving englacial communication ranges of up to 2300 metres.

Dual-Band Circularly Polarized Antenna Array for 5G Millimeter-Wave Applications

A dual-band miniaturized e-shaped antenna with circular polarization (CP) at 28 and 38 GHz is presented in this work for 5G millimeter-wave applications. Characteristic mode analysis (CMA) is used in the design steps of the antenna. This compact antenna consists of a main radiating patch surrounded by an L-shaped and hat-shaped metallic strips. The design was implemented on a single RO5880 substrate with a thickness of 0.508 mm, and fed by a single coaxial cable. A 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 2 antenna array was also developed and validated. The dimensions of this array were <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.5\,\,\lambda _{0}\,\,\times \,\,1.86\,\,\lambda _{0}$ </tex-math></inline-formula> (where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the free space wavelength at 28 GHz). In the lower band of 28 GHz, 95% total efficiency and 12.69 dBiC gain were obtained, while in the higher band of 38 GHz, 90% total efficiency and 11.10 dBiC gain were achieved. The beamforming capability of this dual band array was investigated as well.

Circularly‐polarized cavity‐backed slot antenna array with simplified feeding structure

A class of circularly-polarized cavity-backed slot antenna arrays with simplified feeding structure are proposed. Power dividing network is an essential feeding structure for the design of conventional antenna arrays, which results in complicated antenna structure. A novel feeding technique based on the electric field of cavity modes is introduced to feed the array elements. The slots on the top wall are directly fed by the electric field without additional feeding structure. Crossed slots with different lengths are introduced to achieve the self-phased CP radiation as they produce different perturbation on the two degenerate cavity modes. Therefore, high efficiency and simple antenna structure of the CP slot antenna array are achieved. Then, two CP slot arrays with 3 × 3 and 8 × 8 elements are presented to show the designed feasibility. Finally, the 3 × 3 CP antenna array is fabricated and measured to validate the design concept, which can achieve 12.6 dBic gain, 94% total efficiency, 80% aperture efficiency, and −25 dB cross polarization.

Circularly polarized scanning phased array antenna based on circular polarizer

A circularly polarized (CP) scanning phased array antenna based on circular polarizer is proposed. An efficient technique is developed to introduce the novel scheme of the designed patch antenna and circular polarizer, which are coupled with a small gap. The new approach of fission transmission of electromagnetic (FTEM) wave is developed to transform linear-to-circularly polarized waves. The designed structure is composed of a 2×8 double-layer array with a small gap, which enhances the wide-angle beam scanning capability of ± 20° with high gain at distinct frequencies. The axial ratio (AR) is below 3 dB and exhibits a 4.80% bandwidth from 5.14 GHz to 5.36 GHz with a 13 dBic maximum gain. This new concept is theoretically and experimentally investigated to evaluate the performance of the proposed structure. The proposed structure shows promising potential for applications in radar and satellite communication systems.

3D‐printed circularly polarized concave patch with enhanced bandwidth and radiation pattern

AbstractIn this article, a novel design of a probe‐fed circularly polarized (CP) patch antenna on a 3D‐printed concave‐shaped substrate is proposed. The radiating patch conforms to the concavity of the substrate surface, and the circular polarization is achieved by two pairs of asymmetric slot perturbation. The varying substrate thickness due to the concavity across the cross‐section enhances the antenna's bandwidth by 1.99% compared to traditional flat substrates. The spherically curved surface focuses the antenna's radiation by narrowing its half‐power beam‐width (HPBW). The gain and axial ratio of the antenna are also less susceptible to the effects of having a large ground plane. The results are verified by comparing the measured performance of the proposed antenna with that of a conventional corner truncated CP patch on a 3D‐printed flat substrate. The proposed antenna is designed for sub‐GHz industrial, scientific, and medical radio (ISM) band (865‐868 MHz) and has 7 dBiC gain and near 0 dB axial ratio with 65° and 61° HPBW in elevation, and azimuth planes, respectively.

A broadband directional circularly polarized spiral antenna on EBG structure

ABSTRACT A new low profile broadband directional spiral antenna design on a planar EBG structure is introduced which is suitable for aircraft structural integration. The proposed antenna has the (greater than 4 dBiC) gain and axial ratio (less than 3-dB) bandwidth of 400–800 MHz (except for a narrow frequency range of 505–530 MHz) within a total thickness of one tenth of the wavelength. Meausured peak gain is 7.5 dBiC while gain at 400 and 500 MHz are 6 and 7.2 dBiC, respectively. Abbreviations: EBG: Electromagnetic Bandgap; HIS: High Impedance Surface; SATCOM: Satellite Communications; UHF: Ultra High Frequency; CP: Circularly Polarized; BW: Bandwidth; AR: Axial Ratio

Polarization Enhancement of Microstrip Antennas by Asymmetric and Symmetric Grid Defected Ground Structures

A new approach to controlling cross-polarization (XP), for either suppressing XP or exciting circular polarization (CP), in single-fed microstrip antennas using novel grid defected ground structures (GDGSs) is proposed. The key idea of GDGS is to construct defected ground structures (DGSs) from a grid of etched slots on a ground plane. The properties of each slot can be directly set by using either an open or short with fixed hardwires. The overall fixed hardwire configuration of the GDGS can be found straightforwardly by optimization of the XP or CP characteristics of the microstrip antenna. The importance of the approach is demonstrated by the results achieved. Results from two experimental prototypes are provided that demonstrate XP can be suppressed by 15 dB and CP can be excited with 78 MHz (2.2%) 3-dB axial ratio (AR) bandwidth and 6.6 dBic gain respectively on single-fed microstrip patch antennas.

Design of Low-Sidelobe Circularly Polarized Loop Linear Array Fed by the Slotted SIW

A novel loop linear array for circularly polarized (CP) radiation with low sidelobe levels (SLLs) and high gains is proposed in this letter. The resonant element consists of a pair of loops fed by a slot. Moreover, two square patches are added on the opposite corners of both loops to implement circular polarization. Fed by the slotted substrate integrated waveguide, a 10-element linear array with Taylor distribution is then designed, manufactured, and measured. Measured results show that the fabricated array has bandwidths of 350 MHz (9.76–10.11 GHz) with the reflection coefficients better than −10 dB and 280 MHz (9.82–10.10 GHz) with the axial ratios (ARs) less than 3 dB, respectively. In addition, −22 dB peak SLL, 15.4 dBic gain, −29.6 dB cross-polarization level, namely 0.57 dB AR at the boresight, and 65% aperture efficiency are experimentally obtained at the center frequency.

A compact circularly‐polarized GPS antenna using LTCC technology

ABSTRACTA circularly‐polarized GPS antenna for L1 (1575 MHz) is designed and fabricated using low temperature cofired ceramic (LTCC) technology. A parallel patch and high dielectric constant composite ceramic with LTCC fabrication method are employed to design a compact structure. The electrical connected parallel patch interval and size are the main parameters for achieving resonance frequency at L1‐band to support modern GPS coding schemes. The proposed electrically connected upper and lower patches are connected together with vertical via pins and therefore did not have any connection with the ground plane. By embedding a truncated corner patch and rectangular slots to this design, the right‐hand circularly‐polarized (RHCP) field property is achieved. By using these features, a compact simple CP‐GPS antenna with 2.32 dBic gain at 1575 MHz is designed and fabricated. The proposed antenna has a total compact size of 15 × 15× 4 mm3and operates over the frequency band from 1570 to 1585 MHz for VSWR &lt; 2. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2926–2930, 2016

Millimeter-Wave Wideband High-Efficiency Circularly Polarized Planar Array Antenna

A Ka-band circularly polarized (CP) planar array antenna with wide axial ratio (AR) bandwidth and high efficiency is presented in this paper. A crossed slot with four parasitic patches is proposed as the CP element, which is fed by a unique 90° delay line. There are three minimal AR points within the operational frequency band to widen the bandwidth. The 90° delay line has three branches to realize the phase delay, the amplitude compensation, and the impedance matching, respectively. Thus, the design process is clear and simple. Several short-circuited posts are added in the feeding layer to suppress the TEM wave propagating outside the feeding network. Simulated results of the element show an AR bandwidth ( $\text{AR} ) of 21.2% from 25.3 to 31.3 GHz and a gain of 5.7–6.7 dBic over the same frequency band. Measured results of a fabricated $4 \times 4$ array demonstrate about 14% AR bandwidth and more than 17.4 dBic gain within the frequency band of 26.4–30.3 GHz. The maximum realized gain reaches to 18.2 dBic. The array antenna with a waveguide transition is fabricated through multilayer PCB process and has a size of $72\;\text{mm} \times 48\;\text{mm} \times 2.2\;\text{mm}$ .

Circularly Polarized Meshed Patch Antenna

In this letter, circularly polarized meshed patch antenna has been investigated. A new technique is proposed to provide circular polarization for meshed patch antenna. Moreover, two mesh configurations have been studied, and their opto-radio-electrical performances have been compared to each other. It is shown that there is a conflict between optical transparency and bandwidth of the antennas. Additionally, the Proximity coupling technique has been modified to feed the meshed patch providing more optical transparency for the whole assembly. In the current study, two fabricated circularly polarized meshed patch antennas are presented, one with copper ground plane, another with solar cell ground plane. Measurement results show 2.79% and 3.27% axial-ratio bandwidth (3 dB) at center frequency of 2.43 GHz as well as 4.9 and 4.4 dBiC gain for meshed patch antennas with copper and solar cell ground plane, respectively .

Wideband subwavelength‐profile circularly polarised array antenna using anisotropic metasurface

A cost-effective solution for the performance enhancement of circularly polarised array antennas by using a thin metasurface is proposed. The array is considered as reconfigurable, where an antenna engineer can arbitrarily add the metasurface onto the original array according to application requirements. Once added, the new array forms a subwavelength cavity having a compact form factor of 1.63λ o × 1.63λ o × 0.07λ o at 2.45 GHz. The array antenna is demonstrated to have remarkable enhancement on its performance metrics including boresight gain (12.8 dBic), axial-ratio bandwidth (46.5%) and 10 dBic gain bandwidth (24.4%). More interestingly, a sidelobe suppression level of 4.4 dB is achieved.

Miniaturized Circularly-Polarized Antenna Based on Four Meandered Monopoles

This paper presents a miniaturized circularly-polarized antenna based on four meandered monopoles. The proposed antenna is a dual-substrate type, where four meandered monopoles printed on the upper substrate are fed by a series feed network on the lower substrate. Two substrates are connected by a metal post enclosed by a teflon cylinder. The antenna miniaturization is realized by highly meandering monopole arms and transmission lines of the feed network with the size reduction of 78%. Short-circuit stubs for impedance matching of meandered monopoles are employed on the lower substrate for structural simplicity. The fabricated antenna has a dimension of 0.11×0.11×0.022 λ0, -1.9dBic gain, 1.4dB axial ratio, and 11.5dB front-to-back ratio at 915MHz.

Circularly polarised array antenna with cascade feed network for broadband application in C‐band

A new configuration of a circularly polarised square slot antenna (CPSSA) array operating in C-band is presented. The array consists of 2 × 2 CPSSA elements and is fed by a novel feeding network consisting of the circuit stripline couplers and delay lines. The proposed feeding technique is applied to the 2 × 2 antenna array to increase the axial ratio (AR) bandwidth. The measured impedance bandwidth for a voltage standing wave ratio (VSWR) <2 is around 78.5% (3.4–7.8 GHz), the 3 dB AR bandwidth is about 35.7% (4.6–6.6 GHz) and the antenna has an average 14.2 dBic gain over the 3 dB AR bandwidth. The measured results corroborate well with the simulated results.

Novel Co-planar Waveguide (CPW)-Fed Small Antenna with Circular Polarization

A planar circularly-polarized (CP) small antenna is proposed. To obtain a low profile configuration, a co-planar waveguide (CPW) structure is employed. Circular polarization is achieved using a curved stub that generates current distribution in a direction orthogonal to the current distribution from the patch. Using meander lines and a series gap capacitance, a 70% size reduction is achieved compared to a half-wavelength resonant antenna. To the best of the authors' knowledge, the proposed antenna is the smallest CP antenna using CPW technology. The measured 3dB axial ratio bandwidth is 8.3% from 3.83GHz to 4.16GHz, and a 1.6dBic gain and 89% efficiency are achieved.

Tunable Miniaturized Patch Antennas With Self-Biased Multilayer Magnetic Films

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Magneto-dielectric substrates with thin magnetic films show great potential in realizing electrically small tunable antennas with enhanced bandwidth, improved directivity, and high efficiency. This communication introduces self-biased NiCo-ferrite magnetic films as a practical mean to tune a patch antenna by loading single layer and multilayer self-biased ferrite films. The central resonant frequency of the unloaded patch antenna is measured at 2.1 GHz with a bandwidth of 18 MHz. However, with ferrite loading of the alumina substrate, this frequency is shown to be tunable within a range of 12 MHz–40 MHz, and the antenna efficiency is increased from 41% of the non-magnetic antenna to 56%, 65%, and 74% for the three magnetic antennas. The omnidirectional radiation pattern is significantly enhanced with the <formula formulatype="inline"> <tex Notation="TeX">${-}5$</tex></formula> dBic gain beamwidth increased from 140<formula formulatype="inline"><tex Notation="TeX">$^{\circ}$</tex></formula> to 155<formula formulatype="inline"><tex Notation="TeX">$^{\circ}$</tex></formula>, 156<formula formulatype="inline"><tex Notation="TeX">$^{\circ}$</tex></formula> and 160<formula formulatype="inline"><tex Notation="TeX">$^{\circ}$</tex></formula>, respectively for the three ferrite loaded antennas. In addition, the gains of the three magnetic antennas are enhanced by 0.32, 0.77, and 1.1 dB, respectively, over the unloaded antenna. </para>

Miniature Continuous Coverage Antenna Array for GNSS Receivers

This letter presents a miniature conformal array that provides continuous coverage and good axial ratio from 1100-1600 MHz. Concurrently, it maintains greater than 1.5 dBic RHCP gain and return loss less than -10 dB. The four element array is comprised of two-arm slot spirals with lightweight polymer substrate dielectric loading and a novel termination resistor topology. Multiple elements provide the capability to suppress interfering signals common in GNSS applications. The array, including feeding network, is 3.5 times 3.5 times 0.8 in size and fits into the FRPA-3 footprint and radome.

Circularly polarised equilateral triangular patch array antenna for mobile satellite communications

A satellite-tracking left-handed circularly polarised triangular-patch array antenna has been developed to support the next generation of mobile satellite communications using Japanese Engineering Test Satellite VIII. The targeted minimum gain of the antenna was set to 5 dBic at an elevation of 48° in the Tokyo area, for applications of about a hundred kbit/s data transfer. The antenna is composed of three equilateral triangular patches and fed by a dual-proximity feed. The influence of the array configuration on the characteristic of this antenna is investigated using a method of moments (MoM) approach and a simple point source model. The measurement of the fabricated antenna was then performed to confirm the simulation results. The result showed that the 10 mm distance between the patch apex to the centre of the array antenna satisfies the target. The frequency characteristic of the fabricated antenna is 0.7% shifted to the higher frequency, and the maximum gain is 0.9 dB lower than the simulation results. The result also shows that the characteristic of the patch array antenna satisfies the specification at elevation angle El=48°, especially the 5 dBic gain coverage of the results covers the whole azimuth angle in a conical-cut plane at El=48°.