Stacked Patch Research Articles

Reinforcement around holes in composite materials by use of patched metal inserts

Metal inserts are sometimes used to improve the load carrying capacity of bolted joints in composite materials. In this paper a new concept is introduced where inserts are built during composite manufacturing by integrating stacked metal patches at locations where holes are to be made after consolidation. Initial tests and a parameter study enable more informed design, and specimens with improved stacked inserts are then produced and tested. The specimens with inserts show up to 60% strength improvement in pin-loaded tests. In addition to the experimental work, finite element analysis is performed to investigate the stress fields and the failure mechanisms. The model indicates that the singular stresses at the multi-material corner points are governing for the strength and give indications of the failure mechanisms. Some basic analytical estimates are also presented.

Circularly polarized stacked patch antenna array with enhanced bandwidth for S‐band applications

In this article, a circularly polarized coupled slot 1 × 4 stacked patch antenna array with enhanced bandwidth is proposed for S-band applications. Initially, a patch antenna radiating at 2.79 GHz is designed and maximum energy from feedline to patch element is coupled using two rectangular slots. Whereas, a parallel feedline structure is designed to provide polarization flexibility by creating 0, 90, and 180o phase differences. Then, a truncated patch element is vertically stacked in the design to achieve broader bandwidth of 600 MHz over frequency range from 2.4 to 3.0 GHz. Finally, a coupled slot 1 × 4 array stacked antenna array having feedline line structure to provide 90o phase difference for circular polarization is designed and fabricated for measurements. It is observed that the final design achieved target specification having impedance matching (|S11| (dB) < −10 dB over 2.4 to 3.0 GHz, broad band circular polarization, and 11.5 dBic total gain. Overall, a good agreement between simulated and measurement results is observed.

A Transmitter System-in-Package at 300 GHz With an Off-Chip Antenna and GaAs-Based MMICs

This paper presents a novel transmitter system for applications operating in the frequency region around 300 GHz. A relatively simple packaging approach is taken, allowing for a variety of integrated or embedded applications. This paper presents a multilayered stacked patch antenna on quartz with a dielectric lens, functioning in tandem with a GaAs-based multiplier chain. When operating, an input signal between 7.8 and 8.6 GHz is multiplied 36 times to a frequency range between 280 and 310 GHz, via two in-house fabricated GaAs-based monolithic microwave integrated circuits (MMICs). The antenna is fabricated on quartz wafers via an in-house process. Both, the MMICs and the antenna, are placed on a printed circuit board. A high-density polyethylene lens encloses the system-in-package (SiP), with a footprint of 1 cm $^{2}$ . The SiP has a center frequency of 300 GHz and an absolute pattern bandwidth of 21 GHz. The measured antenna gain along the broadside is 23 dBi, which corresponds to an equivalent isotropic radiated power of 20 dBm. This is achieved with 0.3 W power consumption. The design, simulation, and the analysis are performed via an electromagnetic simulation and modeling tool (Computer Simulation Technology Microwave Studio). Both, separate measurement data for the individual parts of the SiP and complete system experimental characterization are included in this paper.

A Millimeter-Wave Multibeam Transparent Transmitarray Antenna at Ka-Band

This letter presents a transmitarray antenna (TA) in the 27.5–29.5 GHz frequency band. The proposed TA is optically transparent and offers the possibility of steering the beam in the H -plane from –30° to 30°. One can achieve these properties using a novel unit cell, composed of meshed double-circle rings printed on polymethylmethacrylate substrates, a plastic material transparent to visible light. This unit cell provides a phase shift of 300° for an insertion loss lower than 1 dB at 28.5 GHz. In turn, the TA sources consist of 2 × 2-element arrays of aperture-coupled stacked patch antennas. The choice of a patch array over a horn array allows one to reduce the total profile and weight of the TA. We have fabricated and tested a transparent TA with a diameter of 9.9 wavelengths at 28.5 GHz, yielding a broadside gain of 25 dBi and –1 dB gain bandwidth of 1.8 GHz; the off -axis 30° beam presents a peak gain of 21.5 dBi and –1 dB gain bandwidth of 1.4 GHz. The measured results are in good agreement with the simulated ones all over the frequency band of interest.

Compact multi-band stacked circular patch antenna for wideband applications with enhanced gain

ABSTRACTThis paper presents a probe-fed compact multi-band microstrip patch antenna for wideband operation. The proposed antenna is composed of a shorted circular patch fed by folded-patch with a V-shaped slot and two stacked circular patches. Two stacked patches with different diameters are suspended by two shorting pins above the circular patch to achieve a multi-band antenna. The proposed design without stacked patches with a folded-patch feed introduces an ultra-wideband (UWB) antenna with the measured bandwidth of 115.8% in 3.68–13.8 GHz. The proposed stacked design introduces the tuning ability of the frequency bands by changing the diameters of two stacked circular patches. The first and second measured −10 dB bands cover 3.27–4.35 GHz (28.4%) and 5.15–6.40 GHz (21.7%) for worldwide interoperability for microwave access (WiMAX) and wireless local area network (WLAN) operations, respectively. The third measured −10 dB band operates in 9.2–14 GHz with a wide impedance bandwidth (more than 41%). Likewise, good antenna performances such as broadside radiation patterns, acceptable miniaturization and high gain over the operating bands have been observed. Detailed simulations based on the parametric study are performed to identify the triple-band performance of the proposed design.

60 GHz wideband LTCC microstrip patch antenna array with parasitic surrounding stacked patches

This work presents a wideband 60 GHz microstrip patch antenna (MPA) array based on low-temperature co-fired ceramic (LTCC) multilayer technology. Four parasitic patches are stacked above the driven MPA. An additional resonant mode is excited by the proposed parasitic surrounding stacked patches (PSSPs) to enhance the bandwidth of the MPA. The structure of the PSSPs increases the gain of the MPA due to its array configuration. The proposed PSSP structure can find many applications in designs for large-scale antenna arrays because the PSSPs and the driven microstrip patch are distributed at different layers. This arrangement allows a direct feed network to the MPA without the blockage caused by the PSSPs. A 2 × 2 antenna array was designed and fabricated with the PSSPs to further increase its gain. The proposed array can achieve a gain of 10.5 dBi and a wide bandwidth of 27.3% at 60 GHz.

A Substrate Integrated Cavity Backed Filtering Slot Antenna Stacked With a Patch for Frequency Selectivity Enhancement

A patch is proposed to stack above a substrate integrated cavity (SIC) backed filtering slot antenna to enhance antenna frequency selectivity. The antenna is composed of a slot radiator backed by an SIC, a stacked patch, and a microstrip feed line. Two parallel slots are cut onto the top broad wall of the SIC, which is excited by a microstrip line through a nonresonant short slot on the center of the bottom broad wall. The stacked patch is positioned right above the SIC supported by a piece of substrate slab for gain enhancement. Compared with the traditional SIC-backed slot antenna, the proposed antenna achieves higher frequency selectivity as well as enhanced bandwidth and gain. The field distribution and parametric study are conducted to exhibit the operating mechanism of the antenna more clearly. Compared with the conventional SIC-backed slot antenna, the antenna prototype operating at 10 GHz, as example, achieves wider 10 dB impedance matching bandwidth of 8.67%, higher gain of 7.2 dBi, better frequency selectivity of 0.9/0.45 at the lower and upper edges of the operation band, and lower maximum cross-polarization levels of -23/-22 dB in E- and H-planes within the 3 dB beam range, respectively.

ДВУХСЛОЙНЫЕ МИКРОПОЛОСКОВЫЕ АНТЕННЫЕ РЕШЕТКИ ИЗ ПРЯМОУГОЛЬНЫХ ИЗЛУЧАТЕЛЕЙ

PACS numbers: 41.20.Jb, 84.40.Ba Purpose: The purpose of this paper is to propagate the methodology earlier developed by the authors for calculating microstrip antennas for the case of a two-layer antenna array of rectangular radiators, to study its electrodynamics characteristics with expanding its bandwidth. Design/methodology/approach: The research method is based on application of the spectral method in approximation of the given surface current density distribution on the array radiators, when the current density distribution is given by some function wich fairly well discribes the true current distribution and is convenient for further analysis. The essence of the spectral method lies in representation of the Green’s function, the radiation field, and the current density as expansions in the Fourier integral. Such a representation is convenient in analyzing the radiation characteristics of antennas. The investigations were carried out with taking into account the presence of surface waves in the dielectric layers, the mutual influence of the radiators and matching them with the power lines. Findings: Using the developed technique a two-layer microstrip antenna with a grating of four rectangular radiators located on each layer is studied. An algorithm for calculating its characteristics is constructed and its such characteristics as the directivity pattern and the gain factor are investigated. A constructive synthesis of its elements is made that resulted in determination of the dimensions of the radiators of the grating at which they are matching with the power lines. The influence of the layer thickness between the gratings on antenna characteristics is considered. It is shown that using the two-layer structures gives the opportunity to expand the antenna bandwidth, which is of great practical importance. Conclusions: The research methodology makes it possible to investigate the electrodynamics characteristics and to make a constructive synthesis of two-layer microstrip antenna arrays from rectangular radiators having some specified improved parameters, in particular, an extended bandwidth. Key words: radiation, two-layer microstrip antenna, spectral method, surface current density, bandwidth Manuscript submitted 03.07.2018 Radio phys. radio astron. 2018, 23(3): 203-211 REFERENCES 1. POZAR, D. M., 1982. Input impedance and mutual coupling of rectangular microstrip antennas. IEEE Trans. Antennas Propag . vol. 30, is. 6, pp. 1191–1196. DOI: https://doi.org/10.1109/TAP.1982.1142934 2. POZAR, D. M., 1983. Considerations for millimeter wave printed antennas. IEEE Trans. Antennas Propag . vol. 31, is. 5, pp. 740–747. DOI: https://doi.org/10.1109/TAP.1983.1143124 3. POZAR, D. M., 1986. Finite phased arrays of rectangular microstrip patches. IEEE Trans. Antennas Propag . vol. 34, is. 5, pp. 658–665. DOI: https://doi.org/10.1109/TAP.1986.1143868 4. LEVINE, E., MALAMUD, G., SHTRIKMAN, S. and TREVES, D., 1989. A study of microstrip array antennas with the feed network. IEEE Trans. Antennas Propag . vol. AP-37, is. 4, pp. 426–434. DOI: https://doi.org/10.1109/8.24162 5. PROSVIRNIN, S. L. and NECHAEV, YU. B., 1992. Designing of microstrip antennas by using approximation of fixed surface current distribution . Voronezh, Russia: Voronezh State University Publ. (in Russian). 6. PROSVIRNIN, S. L., REZNIK, I. I. and SELEZNEV, D. G., 1998. Matching with feed lines and taking into account interaction in microstrip antenna arrays. J. Commun. Technol. Electron . vol. 43, no. 12, pp. 1376–1379. 7. SELEZNYOV, D. G., REZNIK , I. I. and SELEZNYOV, A. D., 2003. Microstrip Antenna Arrays Composed of Rectangular Radiators. Radio Phys. Radio Astron . vol. 8, is. 1, pp. 52–58 (in Russian). 8. SELEZNYOV, D. G., REZNIK, I. I. and SELEZNYOV, A. D., 2005. Microstrip Antenna Arrays with Dielectric Covering. Radio Phys. Radio Astron . vol. 10, is. 1, pp. 85–91 (in Russian). 9. CROQ, F. and POZAR, D. M., 1991. Millimeter-wave design of wide-band aperture-coupled stacked microstrip antennas. IEEE Trans. Antennas Propag . vol. 39, is. 12, pp. 1770–1776. DOI: https://doi.org/10.1109/8.121599 10. OBUKHOVETS, V. A., KASYANOV, A. O. and ZAGOROVSKY, V. I., 2002. Electromagnetic analysis of multilayered microstrip reflector antenna arrays. Antenny . vol. 4(59), pp. 4–11 (in Russian). 11. YOU, C., TENTZERIS, M. M. and HWANG, W., 2007. Multilayer effects on microstrip antennas for their integration with mechanical structures. IEEE Trans. Antennas Propag . vol. 55, is. 4, pp. 1051–1058. DOI: https://doi.org/10.1109/TAP.2007.893401 12. NAGENDRA PACHAURI, APARNA GUPTA and SONI CHANGLANI, 2015. Analysis of multilayer stacked microstrip patch antenna for bandwidth enhancement. Int. J. Innov. Res. Sci. Eng. Technol . vol. 4, is. 9, pp. 8321–8334. DOI: 10.15680/IJIRSET.2015.04090044

An efficient reflective polarization rotation meta surface for broadband RCS reduction

A compact and broadband reflective polarization rotation meta surface (PRMS) with high polarization conversion ratio (PCR) and radar cross section (RCS) reduction is proposed. A linearly polarized incident electromagnetic (EM) wave is reflected with 90° polarization rotation using the proposed PRMS. The reflective PRMS unit cell consists of complementary stacked quasi fractal patch along with logarithmic stepped patch. This reflective PRMS is printed on stacked FR4 substrates covered by FR4 superstrate and is backed by a ground plane. The patches are connected to the metallic ground using non symmetric metallic vias and the overall dimension of the unit cell in terms of its minimum operating wavelength is only 0.088λ0 × 0.088λ0 × 0.082λ0. A polarization bandwidth of 97.69% with a maximum PCR of 99% is achieved. Further, the proposed reflective PRMS is arranged periodically in a checkerboard surface to obtain a broadband RCS reduction of 10 dB in the required band. A prototype of the checkerboard surface is fabricated and tested for the validation of simulation results. A good pact is obtained between the simulation and experimental results.

Triband planar shared‐aperture antenna array with similar‐shaped radiation patterns

AbstractIn this paper, a triband planar shared‐aperture antenna array is proposed. The proposed antenna array could obtain similar‐shaped radiation patterns at three operating frequency bands. The total structure includes two radiation patch layers, a ground layer and a feeding network layer. Metal vias are used to excite the stacked patches, leading to three resonant frequencies. To verify the proposed antenna array, a 4 × 4 prototype with the overall size of 6.4 × 5.3 × 0.7 cm3 is fabricated and measured. The measured |S11| &lt; −10 dB bandwidths are 13.34–13.82, 17.95‐18.61, and 23.8–25.15 GHz, and measured realized gains are 10.8, 11, and 14.4 dB at 13.5, 18, and 24 GHz.

Mechanically Reconfigurable Linear Array Antenna Fed by a Tunable Corporate Waveguide Network With Tuning Screws

A mechanical technique to provide beam-steering capabilities to a linear array antenna is presented. The methodology is based on the insertion of metallic tuning screws into power dividers in rectangular waveguide technology. These tuning screws establish a short circuit between the top and bottom plates of the waveguide, and a phase change in the transmitted signal is then generated. Therefore, the phase difference between the output ports of a conventional waveguide divider can be controlled with these tuning screws. A corporate waveguide feeding network with several tuning screws has been designed. This tunable waveguide network is used to feed an aperture stacked patch array, forming the final mechanically reconfigurable linear array. Seven different phase configurations have been synthetized by using the tuning screws, which provide a noncontinuous angular scanning. In particular, a main beam steering from −26° to +26° with 13 discrete radiation patterns has been obtained. The use of waveguide technology makes the proposed reconfigurable antenna suitable for low-loss and high-power applications. Total efficiency values higher than 90% have been achieved for every configuration.

A Differentially Driven Dual-Polarized High-Gain Stacked Patch Antenna

A differentially driven dual-polarized high-gain stacked patch antenna is presented in this letter. Two-layer stacked patches are adopted to increase the impedance bandwidth of the antenna. Each of the two stacked patches is inserted with four shorting posts for enhancing the antenna gain. To validate the proposed design, a prototype was meticulously fabricated and tested. The simulated and measured results of the antenna show fractional impedance bandwidths of greater than 19% for differential reflection coefficients less than −10 dB and a high isolation level between the two polarizations ( $ \vert S_{dd21}\vert $ larger than 35 dB). The antenna gain of up to 11 dBi was also measured for the two ports. Furthermore, a good agreement of radiation patterns between simulation and measurement with the cross-polarization levels lower than −16 dB over the whole operating frequency band is achieved.

A Novel Substrate-Integrated Suspended Line Stacked-Patch Antenna Array for WLAN

A novel stacked-patch antenna based on substrate-integrated suspended line technology is proposed. The antenna is designed to be self-packaged using five substrate layers with embedded air cavities. Via is utilized to connect the antenna driven patch with the feed line, and then resonant frequency at 5.2 GHz is generated. U-shaped slot is etched on the antenna driven patch for impedance matching. In order to further extend the impedance bandwidth, a stacked patch with slant slot is introduced and then another resonant frequency at 6.2 GHz is produced. According to the measured results, the antenna element achieves a fractional bandwidth of 17.5% from 5.2 to 6.2 GHz and gain of 9.7 dBi. Based on the antenna element, the eight-element antenna array with feeding network is presented. The microstrip–slotline balun is introduced in the feeding network to achieve 180° phase difference with equal amplitude so that symmetrical radiation patterns are achieved. Simulation and measurement results for the proposed antenna array are in good agreement. In the frequency band from 5.28 to 6.05 GHz, antenna gain of 16.24 dBi with gain flatness variation of 1.5 dB is achieved. In addition, the front-to-back ratio of the self-packaged antenna array is better than 20 dB.

A low‐profile dual‐polarized multilayer parasitic patch array antenna with narrow air gap

AbstractThis article proposes a low‐profile dual‐linear polarized multilayer parasitic patch array antenna, which is composed of 3‐layer printed substrates and 1 air gap layer inserted between the lower and middle substrate. There is 1 slotted square patch printed on the lower substrate with 2 excited probes acting as feeding element, and 1 and 4 slotted square patches are on the middle and upper substrate respectively as parasitic elements. The stacked patches introduce additional dual‐polarized resonances for bandwidth enhancement. Specifically, the T‐ and rectangular slots and T‐stubs are employed near/on the orthogonal axis of the patches in order to achieve impedance matching and to improve 2 orthogonal polarizations. Furthermore, 6 stacked complementary split‐ring resonators (CSRRs) are loaded in the middle and upper substrate mainly for both impedance matching and port isolation adjustment. Simulated and measured results comply with each other, which shows that the fabricated antenna has an operational fractional bandwidth of 6.6% (2.34–2.5 GHz), a maximum gain of 7.9 and 6.9 dB at port 1 and 2 (while 10.2 and 9.3 dBi for the simulated ones), respectively, and port isolation better than 19 dB. In addition, the air‐gap thickness can be maintained at an extremely narrow level of 0.02λ0 (λ0 is the free‐space wavelength at the central frequency).

3-D Printed Inhomogeneous Substrate and Superstrate for Application in Dual-Band and Dual-CP Stacked Patch Antenna

This paper presents the extensive study on the effects of inhomogeneous substrate and superstrate for the exploration of dual-band and dual-circularly polarized patch antenna. As well known to all, the technology for circularly polarized (CP) patch antenna has been often restrictedly achieved by altering the shape of patch conductor surface by a few standard manufacturing processes. Benefited from the 3-D printing technology, it is demonstrated here that CP waves can be alternatively generated via an intact metal patch mounted on low-profile inhomogeneous substrate. As for the inhomogeneous superstrate, low profile is insufficient to make it become a polarizer. As such, a dual-band and dual-CP stacked patch antenna is proposed, where the lower patch and its superstrate exactly serve as the ground and substrate of the upper one. Different impacts of low-profile inhomogeneous substrate and superstrate on polarization are utilized to ensure the isolation of left- and right-hand circular polarizations. Besides, due to the usage of intact patches, two operating bands are independently formed and can be easily located in proximity to each other. A prototype operating at 2.75 and 3.2 GHz is then fabricated and measured. Measured results are found in reasonably a good agreement with the simulated ones.

A Wideband Differentially Fed Dual-Polarized Stacked Patch Antenna With Tuned Slot Excitations

In this communication, a novel wideband differentially fed dual-polarized stacked patch antenna with tuned slot excitations for base station application is proposed. The antenna is composed of a driven patch excited by tuned slot excitations, a parasitic patch to enhance the impedance bandwidth, and a ground plane to obtain unidirectional radiation. Two pairs of the slot excitations etched on the opposite edges of the driven patch are used to obtain dual polarizations. Each tuned slot excitation has an open-ended slot and a $\Gamma $ -shaped feeding line. To connect to the differential circuit easily, a rotated feeding mechanism is adopted. A prototype of the proposed antenna is fabricated and tested. Measured results show that the antenna has a wide differential impedance bandwidth of 49.4% (1.66 to 2.75 GHz) for $\vert \text{S}_{\mathrm{ dd11}}\vert ~f-15 $ dB. In addition, a high differential port isolation of more than 37 dB, a stable radiation pattern with a 3 dB beamwidth of 61°±5°, and a stable gain around 8.7 dBi are obtained within the operational band. The proposed antenna features wideband, high port isolation, and stable gains, and it is a promising candidate for base station systems using differential signals.

Bandwidth Enhancement of Low-Profile Microstrip Antenna for MIMO Applications

This paper includes a design of a four-port stacked patch antenna with band enhancement for multi-in multi-out application. The proposed stacked patch antenna consists of two collocated microstrip patches printed on the upper and lower substrates. Through the analysis of characteristic modes, we find that eight desired modes forced to resonant at the operating band. By exciting the resonant modes on the lower patch, four different radiation patterns are achieved. For each radiation pattern, there are three resonance frequencies at interested frequency band—two parallel resonances and one series resonance—which have been combined to form a wider operating band. The proposed antenna is operating at 2.6 GHz frequency band with at least 7.3% in simulated and 6.5% in measurement impedance bandwidth for each port with low profile. A high port isolation (>24.5 dB) and low correlation (<1e−3) have been achieved. Numerical and experimental results illustrate the validity of the design.

A wideband dual-polarized patch antenna fed with the aperture-coupled microstrip

ABSTRACTIn this paper, a compact broadband dual-polarized stacked patch antenna with the aperture coupled microstrip feed is proposed. By adding a parasitic disc patch, the bandwidth is effectively broadened. Meanwhile, to improve the isolation at the low frequency band, a rectangular slot is etched along the diagonal line of the ground plane. The measured results show that the proposed antenna can operate from 9.6 to 22.4 GHz and the relative bandwidth is 80%. Also, the isolation within the operating frequency band is better than 15 dB and the maximum gain reaches 4.08 dBi.

A High Gain Dual Polarized Ultra-Wideband Array of Antenna for Chipless RFID Applications

In this paper, an ultra-wideband, orthogonally polarized, and high-gain microstrip patch antenna array with $8\times8$ -element for the chipless radio frequency identification (RFID) applications is proposed. This planar-structure antenna has a high front-to-back ratio in a wide frequency band. The element comprises an interleaved aperture-coupled dual polarized stacked microstrip patch antenna with air gaps and complementary back reflectors. The stacked patch elements are etched on Taconic TLX-8 substrate and the complementary back reflectors are etched on FR-4. The presence of back reflectors reduces the back-lobe level significantly. The antenna array operates over 4.2–7.1 GHz and yields 26-dBi gain. Overall, the antenna yields 51.3% fractional bandwidth centred at 5.65 GHz. The antenna can read a multi-bit chipless RFID at a distance of 8 m with a transmit power of −10 dBm.

Low-Profile Dual-Band Stacked Microstrip Monopolar Patch Antenna for WLAN and Car-to-Car Communications

In this paper, a low-profile dual-band stacked microstrip monopolar patch antenna is proposed. By utilizing a stacked-patch configuration, a dual-band property is achieved. A coupled annular ring and a set of conductive vias are loaded into the antenna structure to widen the impedance bandwidth. In order to verify the performance of the proposed antenna, a fully functional prototype was fabricated and measured. The measured results demonstrate that the antenna can achieve impedance bandwidths from 2.24 to 2.53 GHz in the low band and from 5.42 to 5.98 GHz in the high band, separately. Within the operating frequency, omnidirectional radiation patterns are also observed. Besides, the proposed antenna possesses a low-profile structure with a height of 4.175 mm or $0.057\lambda _{0}$ (where $\lambda _{0}$ is the free-space wavelength of 4.1 GHz), which can be easily hidden on the top of a vehicle. With these merits, the proposed design is very appropriate for wireless local area network (2.4–2.48 GHz and 5.75–5.825 GHz) and car-to-car (5.85–5.925 GHz) communications.