Showing papers on "Coaxial antenna published in 2014"

Study and prototyping of practically large-scale mmWave antenna systems for 5G cellular devices

Abstract: This article discusses the challenges, benefits and approaches associated with realizing largescale antenna arrays at mmWave frequency bands for future 5G cellular devices. Key design considerations are investigated to deduce a novel and practical phased array antenna solution operating at 28 GHz with near spherical coverage. The approach is further evolved into a first-of- a-kind cellular phone prototype equipped with mmWave 5G antenna arrays consisting of a total of 32 low-profile antenna elements. Indoor measurements are carried out using the presented prototype to characterize the proposed mmWave antenna system using 16-QAM modulated signals with 27.925 GHz carrier frequency. The biological implications due to the absorbed electromagnetic waves when using mmWave cellular devices are studied and compared in detail with those of 3/4G cellular devices.

A Compact, Low-Profile Metasurface-Enabled Antenna for Wearable Medical Body-Area Network Devices

Abstract: We propose a compact conformal wearable antenna that operates in the 2.36-2.4 GHz medical body-area network band. The antenna is enabled by placing a highly truncated metasurface, consisting of only a two by two array of I-shaped elements, underneath a planar monopole. In contrast to previously reported artificial magnetic conducting ground plane backed antenna designs, here the metasurface acts not only as a ground plane for isolation, but also as the main radiator. An antenna prototype was fabricated and tested, showing a strong agreement between simulation and measurement. Comparing to previously proposed wearable antennas, the demonstrated antenna has a compact form factor of 0.5 λ 0 ×0.3 λ 0 ×0.028 λ 0 , all while achieving a 5.5% impedance bandwidth, a gain of 6.2 dBi, and a front-to-back ratio higher than 23 dB. Further numerical and experimental investigations reveal that the performance of the antenna is extraordinarily robust to both structural deformation and human body loading, far superior to both planar monopoles and microstrip patch antennas. Additionally, the introduced metal backed metasurface enables a 95.3% reduction in the specific absorption rate, making such an antenna a prime candidate for incorporation into various wearable devices.

Compact Printed MIMO Antenna for UWB Applications

Abstract: A compact multiple-input-multiple-output (MIMO) antenna is presented for ultrawideband (UWB) applications. The antenna consists of two open L-shaped slot (LS) antenna elements and a narrow slot on the ground plane. The antenna elements are placed perpendicularly to each other to obtain high isolation, and the narrow slot is added to reduce the mutual coupling of antenna elements in the low frequency band (3-4.5 GHz). The proposed MIMO antenna has a compact size of 32 ×32 mm 2 , and the antenna prototype is fabricated and measured. The measured results show that the proposed antenna design achieves an impedance bandwidth of larger than 3.1-10.6 GHz, low mutual coupling of less than 15 dB, and a low envelope correlation coefficient of better than 0.02 across the frequency band, which are suitable for portable UWB applications.

Design of Polarization Reconfigurable Antenna Using Metasurface

Abstract: A planar polarization-reconfigurable metasurfaced antenna (PRMS) designed using metasurface (MS) is proposed. The PRMS antenna consists of a planar MS placed atop of and in direct contact with a planar slot antenna, both having a circular shape with a diameter of 78 mm (0.9 $\lambda_{0}$ ), making it compact and low profile. By rotating the MS around the center with respect to the slot antenna, the PRMS antenna can be reconfigured to linear polarization, left-hand and right-hand circular polarizations. An equivalent circuit is used to explain the reconfigurability of the antenna. The PRMS antenna is studied and designed to operate at around 3.5 GHz using computer simulation. For verification of simulation results, the PRMS antenna is fabricated and measured. The antenna performance, in terms of polarization reconfigurability, axial-ratio bandwidth, impedance bandwidth, realized boresight gain and radiation pattern, is presented. Results show that the PRMS antenna in circular polarizations achieves an operating bandwidth of 3.3–3.7 GHz (i.e., fractional bandwidth 11.4%), a boresight gain of above 5 dBi and high-polarization isolation of larger than 15 dB. While the PRMS antenna in linear polarization achieves a gain of above 7.5 dBi with cross-polarization isolation larger than 50 dB.

A Broadband Dual-Polarized Planar Antenna for 2G/3G/LTE Base Stations

Abstract: A broadband dual-polarized planar antenna is proposed for 2G/3G/LTE base stations. The dual-polarized antenna is composed of two perpendicularly crossed bow-tie dipoles. Each bow-tie dipole is excited by a microstrip stub that is directly fed by a coaxial line, making the dual-polarized antenna full planar. Due to the coupling between two crossed bow-tie dipoles, a broad bandwidth is achieved. It is shown that the dual-polarized antenna has a bandwidth of 45% (1.7-2.7 GHz) for return loss >15 dB with an isolation of higher than 30 dB between two polarization input ports. The dual-polarized antenna has a half-power beam width (HPBW) of around 65 ° and an average gain of 8.5 dBi for slant ±45° polarizations. An 8-element dual-polarized planar antenna array is developed for base station applications. A bandwidth of 56% (1.63-2.9 GHz) is obtained for the antenna array. The antenna gain of the array is about 16 dBi and the HPBW is 65±8° for each polarization.

Compact Printed UWB Diversity Slot Antenna With 5.5-GHz Band-Notched Characteristics

Abstract: A novel compact printed ultrawideband (UWB) slot antenna for MIMO/diversity applications is presented in this letter. The antenna consists of two modified coplanar waveguides (CPWs) feeding staircase-shaped radiating elements for orthogonal radiation patterns, where a rectangle stub is placed at 45° between the CPW to ensure high isolations. By etching two split-ring resonator (SRR) slots on the radiators respectively, the band-notched property is achieved. Results show that this antenna meets a 10-dB impedance bandwidth and 15 dB isolation from 2.5 to 12 GHz, with a notched band at 5.5 GHz. The measurements of the radiation patterns and envelope correlation coefficient (ECC) denote that the antenna is suitable for multiple-input-multiple-output (MIMO)/diversity systems. Furthermore, it has a compact size of 48 × 48 mm2, which has been significantly reduced, and it is a good candidate for portable devices.

A Compact Microstrip-Fed Triple Band-Notched UWB Monopole Antenna

Abstract: In this letter, a novel low-profile microstrip-fed compact triple band-notched ultrawideband (UWB) antenna is proposed. Notch bands around the 3.3-3.8-GHz WiMAX and 5.15-5.85-GHz WLAN frequencies are obtained by etching out two elliptic single complementary split-ring resonators (ESCSRRs) of different dimensions from the radiating patch of the antenna. Furthermore, by placing two rectangular split-ring resonators near the feedline-patch junction of the antenna, rejection for the 7.9-8.4-GHz X-band frequencies is achieved. Design guidelines for implementing the notch-bands at the desired frequency regions are provided. The match between the simulated and experimental results suggests that the proposed antenna can be a good candidate for application in UWB communication systems.

Capacitively Loaded Circularly Polarized Implantable Patch Antenna for ISM Band Biomedical Applications

Abstract: A single-fed miniaturized circularly polarized microstrip patch antenna is designed and experimentally demonstrated for industrial-scientific-medical (2.4-2.48 GHz) biomedical applications. The proposed antenna is designed by utilizing the capacitive loading on the radiator. Compared with the initial topology of the proposed antenna, the so-called square patch antenna with a center-square slot, the proposed method has the advantage of good size reduction and good polarization purity. The footprint of the proposed antenna is 10×10×1.27 mm3. The simulated impedance, axial ratio, and radiation pattern are studied and compared in two simulation models: cubic skin phantom and Gustav voxel human body. The effect of different body phantoms is discussed to evaluate the sensitivity of the proposed antenna. The effect of coaxial cable is also discussed. Two typical approaches to address the biocompatibility issue for practical applications are reported as well. The simulated and measured impedance bandwidths in cubic skin phantom are 7.7% and 10.2%, respectively. The performance of the communication link between the implanted CP antenna and the external antenna is also presented.

Low-Profile Dual-Band Textile Antenna With Artificial Magnetic Conductor Plane

Abstract: A dual-band textile antenna loaded with an artificial magnetic conductor (AMC) plane is proposed for WLAN applications. Its dual-band operation is enabled by a rectangular patch in the 2.4 GHz band and a patch-etched slot dipole in the 5 GHz band. Since the AMC approaches a perfect magnetic conductor (PMC) in the 5 GHz band, the slot dipole can be located close to the ground. The proposed antenna is fully fabricated using textiles except for a feeding connector used for testing purposes and a via. Simulations and experiments agree well and validate that this low profile antenna operates with a good reflection coefficient and a high front-to-back ratio (FBR) within the desired bands.

A Wideband Circularly Polarized Cross-Dipole Antenna

Abstract: This letter introduces a wideband circularly polarized (CP) cross-dipole antenna fabricated on a double-layered printed circuit board (PCB) substrate for 2.45-GHz ISM band wireless communications. Unlike conventional cross-dipole antennas, the proposed cross dipole is designed with wide open ends such that both impedance and axial-ratio (AR) bandwidths are enhanced. In addition, to excite the CP radiation effectively, a curved-delay line providing an orthogonal phase difference among the cross-dipole elements is attached at the corners of the sequentially rotated elements. By choosing a proper radius of the curved-delay line, a wide input impedance of the antenna can be realized. The antenna is center-fed by a 50- Ω coaxial cable and is placed above a square reflector to obtain a directional CP radiation pattern. With the advantage of centered feed, symmetric CP radiation patterns can be achieved across the entire operating bandwidth. Simulated and measured results confirm the proposed antenna produced good CP characteristics. An impedance bandwidth (for VSWR ≤ 2) of about 50.2% (1.99-3.22 GHz) and the 3-dB AR bandwidth of about 27% (2.30-2.9 GHz) around the center frequency of 2.45 GHz were measured. The antenna has an average CP gain of 6.2 dBic across the operating bandwidth and the maximum gain of 6.8 dBic at the center frequency. The size of antenna is 0.45λ×0.45λ×0.24λ.

Circularly Polarized Helical Antenna for ISM-Band Ingestible Capsule Endoscope Systems

Abstract: A multilayer miniaturized circularly polarized (CP) helical antenna is designed and experimentally demonstrated for industrial, scientific, and medical (ISM) (2.4-2.48 GHz) ingestible capsule endoscope systems. The proposed antenna is composed of three open loops at various layers connected by via holes to form an axial-mode helical structure to generate traveling wave radiation. A one-layer muscle phantom model is used for initial design and optimization. The footprint of the proposed antenna is π×(5.5) 2 ×3.81 mm 3 . The simulated and measured impedance bandwidth is over 40% and 26% in the one-layer muscle phantom, respectively. The simulated axial ratio (AR) bandwidth is around 33.3%. The CP purity of the proposed antenna is calculated by comparing the communication link levels for two orthogonal polarizations. Additionally, electrical components are modeled inside the capsule to evaluate the effects on the antenna performance. CST voxel Gustav human body is utilized to study the design in a realistic environment. Finally, an omnidirectional CP exterior antenna is designed and the communication link is evaluated.

A Compact Dual-Polarized Printed Dipole Antenna With High Isolation for Wideband Base Station Applications

Abstract: A compact dual-polarized printed dipole antenna for wideband base station applications is presented in this communication. The proposed dipole antenna is etched on three assembled substrates. Four horizontal triangular patches are introduced to form two dipoles in two orthogonal polarizations. Two integrated baluns connected with 50 Ω SMA launchers are used to excite the dipole antenna. The proposed dipole antenna achieves a more compact size than many reported wideband printed dipole and magneto-electric dipole antennas. Both simulated and measured results show that the proposed antenna has a port isolation higher than 35 dB over 52% impendence bandwidth (VSWR <; 1.5). Moreover, stable radiation pattern with a peak gain of 7 dBi - 8.6 dBi is obtained within the operating band. The proposed dipole antenna is suitable as an array element and can be used for wideband base station antennas in the next generation IMT-advanced communications.

Method and apparatus for high-performance compact volumetric antenna with pattern control

Abstract: A wide-bandwidth antenna with antenna pattern control includes a radiator and a feed. The radiator includes two or more volumetric radiating elements. The feed includes two or more feed units, the feed units configured to provide wave signals to the volumetric radiating elements. The feed units provide an independent signal for each radiating element. The wave signals can be fed out of phase to each other. Depending on the dielectric filler inside the volume of the antenna and the phase shift between feeds, the pattern can be modified electronically leading to pattern control. The radiating elements are spaced at a distance at least one order of magnitude smaller than half of an operational wavelength of the antenna. At least one electrically conductive element of the antenna is capable of conducting a current that generates a magnetic field. The magnetic field lowers the total reactance of the antenna, thereby resulting in enhanced performance of the antenna in terms of bandwidth, gain, and pattern control. The volumetric design allows miniaturization of the antenna.

Frequency-Reconfigurable Antenna Using Metasurface

Abstract: A frequency-reconfigurable antenna designed using metasurface (MS) to operate at around 5 GHz is proposed and studied. The frequency-reconfigurable metasurfaced (FRMS) antenna is composed of a simple circular patch antenna and a circular MS with the same diameter of 40 mm (0.67 λ) and implemented using planar technology. The MS is placed directly atop the patch antenna, making the FRMS antenna very compact and low profile with a thickness of only 3.048 mm (0.05 λ). The MS consists of rectangular-loop unit cells placed periodically in the vertical and horizontal directions. Simulation results show that the operating frequency of the antenna can be tuned by physically rotating the MS around the center with respect to the patch antenna. The MS placed atop the patch antenna behaves like a dielectric substrate and rotating the MS changes the equivalent relative permittivity of the substrate and hence the operating frequency of the FRMS antenna. Measured results show that the antenna has a tuning range from 4.76 to 5.51 GHz, a fractional tuning range of 14.6%, radiation efficiency and a realized peak gain of more than 80% and 5 dBi, respectively, across the tuning range.

Wideband Millimeter-Wave Substrate Integrated Waveguide Cavity-Backed Rectangular Patch Antenna

Abstract: In this letter, a new type of wideband substrate integrated waveguide (SIW) cavity-backed patch antenna and array for millimeter wave (mmW) are investigated and implemented. The proposed antenna is composed of a rectangular patch with a backed SIW cavity. In order to enhance the bandwidth and radiation efficiency, the cavity is designed to resonate at its TE210 mode. Based on the proposed antenna, a 4 × 4 array is also designed. Both the proposed antenna and array are fabricated with standard printed circuit board (PCB) process, which possess the advantage of easy integration with planar circuits. The measured bandwidth (|S11| ≤ -10 dB) of the antenna element is larger than 15%, and that of the antenna array is about 8.7%. The measured peak gains are 6.5 dBi for the element and 17.8 dBi for the array, and the corresponding simulated radiation efficiencies are 83.9% and 74.9%, respectively. The proposed antenna and array are promising for millimeter-wave applications due to its merits of wide band, high efficiency, low cost, low profile, etc.

A Novel Broadband Dual-Polarization Antenna Utilizing Strong Mutual Coupling

Abstract: A novel broadband dual-polarization antenna utilizing strong mutual coupling with high isolation is presented in this communication. The antenna is composed of two orthogonally situated dipoles which have square-loop shape arms (SLSAs). And to shape the radiation pattern of the antenna, a metal reflector is placed under the antenna. By elaborately utilizing the strong mutual coupling between the two dipoles, very good impedance match and sufficiently high isolation can be achieved simultaneously, the reasons for which are analyzed in this communication. Both the simulated and the measured results show that a more than 57.5% impedance bandwidth with SWR 31 dB can be achieved for the proposed antenna. As an important advantage, the input impedance of the antenna can be controlled within certain limits by adjusting the configurations, thus the antenna can be fed directly by coaxial cables without using impedance transformers. Besides, the antenna structure is compact and simple.

Design and analysis of a low-profile 28 GHz beam steering antenna solution for Future 5G cellular applications

Abstract: A first-of-the-kind 28 GHz antenna solution for the upcoming 5G cellular communication is presented in detail. Extensive measurements and simulations ascertain the proposed 28 GHz antenna solution to be highly effective for cellular handsets operating in realistic propagating environments.

Multiband common-caliber antenna

Abstract: An embodiment of the present invention provides a multiband common-caliber antenna. The multiband common-caliber antenna of the present invention comprises a continuous transverse stub (CTS) antenna and a microstrip patch antenna. The CTS antenna comprises a planar waveguide feeding structure and multiple strip-shaped waveguide radiation units disposed on the planar waveguide feeding structure and disposed in a spaced manner along a first direction. A medium substrate is disposed between every two strip-shaped waveguide radiation units and on the upper surface of the planar waveguide feeding structure. Microstrip patch antenna arrays are disposed on the upper surface of the medium substrate. Each of the microstrip patch antenna arrays comprises multiple microstrip patch antenna units disposed in a spaced manner along a second direction perpendicular to the first direction. The number of the microstrip patch antenna arrays disposed on at least one of the medium substrate is not less than 2. The microstrip patch antenna arrays disposed on the medium substrates form the microstrip patch antenna. The embodiment of the present invention suppresses mutual coupling between surface waves of the microstrip patch antenna and the antenna.

Compact and Small Planar Monopole Antenna With Symmetrical L- and U-Shaped Slots for WLAN/WiMAX Applications

Abstract: A small and compact triple-band microstrip-fed printed monopole antenna for Wireless Local Area Network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX) is presented. The proposed antenna consists of a rectangular radiating patch with L- and U-shaped slots and ground plane. A parametric study on the lengths of the U- and L-shaped slots of the proposed antenna is provided to obtain the required operational frequency bands-namely, WLAN (2.4/5.2/5.8 GHz) and WiMAX (2.5/3.5/5.5 GHz). The proposed antenna is small (15 × 15 × 1.6 mm 3) when compared to previously well-known double- and triple-band monopole antennas. The simulation and measurement results show that the designed antenna is capable of operating over the 2.25-2.85, 3.4-4.15, and 4.45-8 GHz frequency bands while rejecting frequency ranges between these three bands. Omnidirectional radiation pattern and acceptable antenna gain are achieved over the operating bands.

A Novel Low-Cost Circularly Polarized Rotated Stacked Dielectric Resonator Antenna

Abstract: A novel low-cost method for generating circular polarization in a dielectric resonator antenna is proposed. The antenna comprises four rectangular dielectric layers, each one being rotated by an angle of 30 ° relative to its adjacent layers. Utilizing such an approach has provided a circular polarization over a bandwidth of 6% from 9.55 to 10.15 GHz. This has been achieved in conjunction with a 21% impedance-matching bandwidth over the same frequency range. Also, the radiation efficiency of the proposed circularly polarized dielectric resonator antenna is 93% in this frequency band of operation

Design and Performance Study of a Dual-Element Multiband Printed Monopole Antenna Array for MIMO Terminals

Abstract: This letter presents a study on linearly polarized compact multiband multiple-input-multiple-output (MIMO) antenna system for small mobile terminals. The MIMO antenna system consists of two symmetric printed monopole antennas with edge-to-edge separation of 0.097 λ0 at 900 MHz. Each antenna element has a capacitive feed and is composed of two twisted lines, a parasitic loop, and a shorting trip that generate five resonant modes around 900, 1800, 2100, 3500, and 5400 MHz, covering GSM850/900, DCS, PCS, UMTS, WLAN, and WiMAX frequency bands. Two inverted-L shaped branches and a rectangular slot with one circular end, etched on the ground plane, were introduced to improve the isolation between antenna elements. The isolation achieved is higher than 15 dB in the lower band and 20 dB in the upper bands, leading to an envelope correlation coefficient of less than 0.025. The simulated performance of the designed antenna system has been verified in the experiment.

High-Efficiency Sea-Water Monopole Antenna for Maritime Wireless Communications

Abstract: This paper presents a study of sea-water monopole antenna at very high frequency (VHF) band for maritime wireless communications. The sea-water monopole antenna consists of a feeding probe and a sea-water cylinder held by a clear acrylic tube. The feeding probe is loaded with a disk on the top to improve the excitation of TM mode. A theoretical study of the sea-water monopole antenna based on the three-term theory is presented, which has not appeared in literature. Commercial software packages ANSYS HFSS and FEKO are used to simulate this antenna. Experimental results of a fabricated sea-water monopole antenna with a radius of 50 mm show reasonably good agreement with theoretical predictions. Measurement shows that the proposed sea-water antenna has high radiation efficiency. Meanwhile, due to the transparency and liquidity of sea water, the proposed antenna is almost optically transparent and can be easily reconfigurable. The center frequency of the antenna is tunable by lengthening or shortening the water cylinder, while the bandwidth of the antenna can be adjusted by widening or narrowing the water cylinder.

Switchable Antennas for Wireless Applications

Abstract: Techniques of designing an antenna array with antenna units controlled electronically are described. Through controlling the combination of the reflectors in each of the antenna units, a desired antenna pattern is formed, adapting to the environment, and providing reliable and efficient links between two transceivers. According to one aspect of the present invention, a switch (e.g., a diode) is used to couple two reflectors. The diode is controlled to be on or off so that the reflectors are conductively integrated or separated.

A Novel, Low-Profile, Vertically-Polarized UWB Antenna for WBAN

Abstract: This paper proposes a novel, low-profile UWB antenna for wireless body area network (WBAN) applications. The antenna has a polarization perpendicular to the body-free-space interface, which is interesting in order to minimize the coupling into the body. Its structure comprises a modified mono-cone with a top-cross-plate and is coaxially fed through the ground plane. The higher frequency band |S11| performance is due to the mono-cone while the top-cross-plate is responsible for the lower frequency band. This plate also leads to a height reduction when compared to conventional mono-cone antennas. A comprehensive parametric study is done to provide design guidelines. Both frequency- and time-domain results have been measured and presented to validate the design. Results show that the antenna operates from 3.06 to beyond 12 GHz based on |S11| ≤ -10 dB, radiates omni-directionally in the H-plane, and has a radiation efficiency over 95%. The system-fidelity factor for UWB signals is adequate for pulse transmission. Finally, the influence of the human proximity on the antenna matching was tested. Results show that its impedance is nearly unchanged as compared to free-space.

A Compact Double-Layer On-Body Matched Bowtie Antenna for Medical Diagnosis

Abstract: A compact double-layer Bowtie antenna optimized for medical diagnosis is presented in this paper. This on-body antenna is matched to the human body to allow more energy to be radiated into the human body to obtain stronger reflections for image processing. By using a Bowtie antenna with double layers as well as a folded structure and meandered microstrip lines at the bottom of the antenna, a small size of 30 × 30 mm2 with a size reduction of 40% is achieved, compared to the reference antenna of 50 × 50 mm2 within the same operational frequency range. After the optimization of the antenna parameters, the antenna is characterized from 0.5 to 2 GHz, where the low frequencies enable a high penetration into human body and the large frequency range contributes to a high bandwidth and hence a fine range resolution. The simulated and measured results are shown with respect to the impedance matching, near-field pattern, gain and SAR distributions. With features such as a very small size, very low operational frequency, high front-to-back ratio, this design shows a high potential for use in medical diagnosis of stroke, breast cancer and water accumulation detection in the human body.

Frequency-Reconfigurable Low-Profile Circular Monopolar Patch Antenna

Abstract: A novel frequency-reconfigurable antenna is presented based on a circular monopolar patch antenna. The antenna comprises of a center-fed circular patch surrounded by four sector-shaped patches. Eight varactor diodes are introduced to bridge the gaps between the circular patch and the sector-shaped patches. By changing the reverse bias voltage of the varactor diodes, the antenna can be switched in the operating frequency. A fully functional prototype is developed and tested, which exhibits a continuously tunable frequency band from 1.64 GHz to 2.12 GHz. The measured efficiency rises from about 45% to about 85% as the operating frequency increases from 1.64 GHz to 2.12 GHz. Stable monopole like radiation patterns are achieved at all operating frequencies. In addition, the antenna owns a low-profile structure (0.04 free-space wavelengths at 1.9 GHz). The frequency selective feature and stable radiation patterns make the antenna potentially suitable for future wireless communication systems, such as cognitive radio.

Compact Quasi-Isotropic Dielectric Resonator Antenna With Small Ground Plane

Abstract: The quasi-isotropic dielectric resonator antenna (DRA) is investigated for the first time. It uses a small ground plane which also serves as an electric dipole. The electric dipole combines with the equivalent magnetic dipole of the DRA to generate quasi-isotropic fields. A choke (balun) is connected to the outer conductor of the coaxial cable to suppress stray radiation. ANSYS HFSS was used to simulate the antenna, and a prototype operating at 2.4-GHz WLAN band was fabricated to verify the simulation. Results show that the difference between the measured maximum and minimum radiation power densities is 5.6 dB over the entire pseudo spherical radiating surface. By using a narrower ground plane and a higher dielectric constant, the gain difference can be reduced to 3.4 dB, approaching the theoretical limit of 3 dB.

Design and Fabrication of a Dual-Polarization Waveguide Slot Array Antenna With High Isolation and High Antenna Efficiency for the 60 GHz Band

Abstract: We propose a slot array antenna for dual-polarization operation in the 60 GHz band. To realize the dual-polarization, cross-shaped radiating slots and a multilayer feeding structure are employed. A 16 $\,\times\,$ 16-element array is fabricated by diffusion bonding of laminated thin copper plates, which has the advantages of high precision and low loss characteristics. To suppress the grating lobes, we employ several design techniques, such as a thick cavity structure and dense element spacing. The high antenna gain higher than 32.0 dBi and the antenna efficiency near 80.0% are obtained over 60.0–64.0 GHz for two different polarizations. The 1-dB-down gain bandwidths reach 10.4% and 10.9%. High isolation above 50 dB is achieved between the two input ports.

Perfect Absorber Metamaterial for Designing Low-RCS Patch Antenna

Abstract: Perfect absorber metamaterial (PAM) to reduce antenna radar cross section (RCS) is proposed. The novel low-RCS antenna is based on the concept of the PAM consisting of a periodic array of metallic dendritic structure and metallic square film etched on each face of a single substrate. The PAM processes high electromagnetic wave absorptivity for a wide incident angle. In the present letter, the PAM patterns are printed on the surface of a patch antenna to reduce the antenna RCS. It is demonstrated that, as compared to an antenna without the PAM, the proposed antenna RCS can be reduced drastically due to the fact that the PAM absorbs electromagnetic wave. Meanwhile, the proposed antenna can still maintain good radiation characteristics.