Showing papers on "Microstrip published in 2011"
TL;DR: In this article, the authors provide an overview of the recent advances in the modelling, design and technological implementation of SIW structures and components, as well as their application in the development of circuits and components operating in the microwave and millimetre wave region.
Abstract: Substrate-integrated waveguide (SIW) technology represents an emerging and very promising candidate for the development of circuits and components operating in the microwave and millimetre-wave region. SIW structures are generally fabricated by using two rows of conducting cylinders or slots embedded in a dielectric substrate that connects two parallel metal plates, and permit the implementation of classical rectangular waveguide components in planar form, along with printed circuitry, active devices and antennas. This study aims to provide an overview of the recent advances in the modelling, design and technological implementation of SIW structures and components.
1,129 citations
TL;DR: In this paper, the ridge gap waveguide is used to verify the large bandwidth and low losses of the quasi-transverse electromagnetic (TEM) mode propagating along the guiding ridge.
Abstract: This study describes the design and experimental verification of the ridge gap waveguide, appearing in the gap between parallel metal plates. One of the plates has a texture in the form of a wave-guiding metal ridge surrounded by metal posts. The latter posts, referred to as a pin surface or bed of nails, are designed to give a stopband for the normal parallel-plate modes between 10 and 23 GHz. The hardware demonstrator includes two 90 bends and two capacitive coupled coaxial transitions enabling measurements with a vector network analyser (VNA). The measured results verify the large bandwidth and low losses of the quasi-transverse electromagnetic (TEM) mode propagating along the guiding ridge, and that 90 bends can be designed in the same way as for microstrip lines. The demonstrator is designed for use around 15 GHz. Still, the ridge gap waveguide is more advantageous for frequencies above 30 GHz, because it can be realised entirely from metal using milling or moulding, and there are no requirements for conducting joints between the two plates that otherwise is a problem when realising conventional hollow waveguides.
377 citations
TL;DR: In this paper, a large electronically reconfigurable reflectarray antenna that has 160 × 160 reflecting elements was designed, fabricated, and evaluated so that it could be applied to a millimeter-wave imaging system operating in the 60 GHz band.
Abstract: A large electronically reconfigurable reflectarray antenna that has 160 × 160 reflecting elements was designed, fabricated, and evaluated so that it could be applied to a millimeter-wave imaging system operating in the 60-GHz band. To make it feasible to construct such a large reflectarray, the reflecting element structure had to be simple and easily controlled; therefore, a reflecting element consisting of a microstrip patch and a single-bit digital phase shifter using a p-i-n diode was employed. A large reflectarray antenna was fabricated using the reflecting elements. The measured radiation patterns and antenna gain were in good agreement with those that were calculated. Furthermore, the near-field beam focusing capabilities, which was required to image near-field objects, were also verified through an experiment. Finally, the response time for beamforming was measured, which was far less than the system requirements.
242 citations
TL;DR: An efficient mutual coupling reduction method is introduced in this article for extremely closely placed dual-element microstrip antennas positioned on a finite-sized ground plane for WLAN MIMO application at 5.8 GHz.
Abstract: An efficient mutual coupling reduction method is introduced in this letter for extremely closely placed dual-element microstrip antennas positioned on a finite-sized ground plane for WLAN MIMO application at 5.8 GHz. High isolation can be achieved through a simple slot structure on the ground between the microstrip antennas. The position, length, and width of the slot have been optimized for maximizing the isolation. It is found that more than 40 dB isolation can be achieved between two parallel microstrip antennas sharing a common ground plane. The space distance of these antennas is 17.5 mm ≈ 0.33λ0 from element center to center (side by side of 1.6 mm ≈ 0.031λ0) when the ground plane size is 0.85λ0 × 0.55λ0. Along with this letter, several prototypes were fabricated, and their performances measured to validate the obtained IE3D moment method-based simulation results.
230 citations
TL;DR: In this paper, a generalized coupled-line circuit structure for a dual-band Wilkinson power divider is proposed, which is composed of two coupled lines with different even-and odd-mode characteristic impedances and two lumped resistors.
Abstract: A novel generalized coupled-line circuit structure for a dual-band Wilkinson power divider is proposed. The proposed power divider is composed of two coupled lines with different even- and odd-mode characteristic impedances and two lumped resistors. Using rigorous even- and odd-mode analysis, the analytical design equations for this proposed power divider are obtained and the ideal closed-form scattering parameters are constructed. Since the traditional transmission line is a special case of coupled line (coupled coefficient is zero), it is found that traditional noncoupled-line dual-band (including single band) Wilkinson power dividers and previous dual-band coupled-line power dividers are special cases of this generalized power divider. As a typical example, which could only be designed by using this given design equations, a compact microstrip 3-dB power divider operating at both 1.1 and 2.2 GHz is designed, fabricated, and measured. There is good agreement between calculated and measured results.
224 citations
Patent•
21 Feb 2011TL;DR: In this paper, a dielectric resonator antenna consisting of a ground plane, operatively coupled with the ground plane and a substrate, having a feeding network consisting of four microstrip lines is presented.
Abstract: The present invention provides a dielectric resonator antenna comprising: a dielectric resonator; a ground plane, operatively coupled with the dielectric resonator, the ground plane having four slots; and a substrate, operatively coupled to the ground plane, having a feeding network consisting of four microstrip lines; wherein the four slots are constructed and geometrically arranged to ensure proper circular polarization and coupling to the dielectric resonator; and wherein the antenna feeding network combines the four microstrip lines with a 90 degree phase difference to generate circular polarization over a wide frequency band.
224 citations
TL;DR: In this paper, four compact asymmetric-slit microstrip antennas were proposed and studied for circular polarization by cutting asymmetrical slits in diagonal directions onto the square microstrip patches, the single coaxial feed microstrip patch antennas were realized for circularly polarized radiation with compact antenna size.
Abstract: Four compact asymmetric-slit microstrip antennas are proposed and studied for circular polarization. By cutting asymmetrical slits in diagonal directions onto the square microstrip patches, the single coaxial-feed microstrip patch antennas are realized for circularly polarized radiation with compact antenna size. The performances of the proposed antennas with several asymmetric-slit shapes onto the patch radiators are compared. The measured 10-dB return loss and 3-dB axial-ratio bandwidths of the antenna prototype are around 2.5% and 0.5%, respectively. The proposed asymmetric-slit configurations are useful for compact circularly polarized microstrip patch antennas and array design.
208 citations
01 Jan 2011
TL;DR: The first edition of Microstrip Filters for RF/Microwave Applications as mentioned in this paper was published in 2001 and has been used extensively in both academia and industry by microwave researchers and engineers.
Abstract: The first edition of “Microstrip Filters for RF/Microwave Applications” was published in 2001. Over the years the book has been well received and is used extensively in both academia and industry by microwave researchers and engineers. From its inception as a manuscript the book is almost 8 years old. While the fundamentals of filter circuits have not changed, further innovations in filter realizations and other applications have occurred with changes in the technology and use of new fabrication processes, such as the recent advances in RF MEMS and ferroelectric films for tunable filters; the use of liquid crystal polymer (LCP) substrates for multilayer circuits, as well as the new filters for dual-band, multi-band and ultra wideband (UWB) applications.
203 citations
TL;DR: The co-design approach for the integration of filter and antenna is introduced and the proposed structure provides good design accuracy and filter skirt selectivity as compared to the filter simple cascade with antenna and a bandpass filter of the same order.
Abstract: Synthesis and design of a new printed filtering antenna is presented in this communication. For the requirements of efficient integration and simple fabrication, the co-design approach for the integration of filter and antenna is introduced. The printed inverted-L antenna and the parallel coupled microstrip line sections are used for example to illustrate the synthesis of a bandpass filtering antenna. The equivalent circuit model for the inverted-L antenna, which is mainly a series RLC circuit, is first established. The values of the corresponding circuit components are then extracted by comparing with the full-wave simulation results. The inverted-L antenna here performs not only a radiator but also the last resonator of the bandpass filter. A design procedure is given, which clearly indicates the steps from the filter specifications to the implementation. As an example, a 2.45 GHz third-order Chebyshev bandpass filter with 0.1 dB equal-ripple response is tackled. Without suffering more circuit area, the proposed structure provides good design accuracy and filter skirt selectivity as compared to the filter simple cascade with antenna and a bandpass filter of the same order. The measured results, including the return loss, total radiated power, and radiation gain versus frequency, agree well with the designed ones.
200 citations
TL;DR: In this article, a novel way capable of improving low-frequency performance of traditional Vivaldi antennas is presented, which is modified via introducing the loading structure, i.e., circular shape-load or slot-load, to match the termination.
Abstract: A novel way capable of improving low-frequency performance of Vivaldi antennas is presented in this paper. Traditional Vivaldi antennas are modified via introducing the loading structure, i.e., circular-shape-load or slot-load, to match the termination. This modified antenna has been demonstrated to have the impedance bandwidth of over 25:1. It also exhibits symmetric radiation patterns in both the E- and H-plane in addition to the gain varying from 3 to 12 dBi in the measurement bandwidth of 4-50 GHz.
198 citations
TL;DR: In this paper, a 2.45 GHz rectifying antenna (rectenna) using a compact dual circularly polarized (DCP) patch antenna with an RF-dc power conversion part is presented.
Abstract: A 2.45-GHz rectifying antenna (rectenna) using a compact dual circularly polarized (DCP) patch antenna with an RF-dc power conversion part is presented. The DCP antenna is coupled to a microstrip line by an aperture in the ground plane and includes a bandpass filter for harmonic rejections. It exhibits a measured bandwidth of 2100 MHz (10 dB return loss) and a 705-MHz CP bandwidth (3 dB axial ratio). The maximum efficiency and dc voltage are respectively equal to 63% and 2.82 V over a resistive load of 1600 Ω for a power density of 0.525 mW/cm2.
TL;DR: The proposed design is an octagonal fractal microstrip patch antenna that can be used for 10 GHz -50 GHz frequency range, i.e., it is a super wideband microstrip antenna with 40 GHz bandwidth.
Abstract: The commercial and military telecommunication systems require ultrawideband antennas. The small physical size and multi-band capability are very important in the design of ultrawideband antennas. Fractals have unique properties such as self-similarity and space-filling. The use of fractal geometry in antenna design provides a good method for achieving the desired miniaturization and multi-band properties. In this communication, a multi-band and broad-band microstrip antenna based on a new fractal geometry is presented. The proposed design is an octagonal fractal microstrip patch antenna. The simulation and optimization are performed using CST Microwave Studio simulator. The results show that the proposed microstrip antenna can be used for 10 GHz -50 GHz frequency range, i.e., it is a super wideband microstrip antenna with 40 GHz bandwidth. Radiation patterns and gains are also studied.
TL;DR: In this article, a new design for single-feed dual-band circularly polarized microstrip antennas is presented, where a stacked patch configuration is used for the antenna, and circular polarization is achieved by designing asymmetrical U-slots on the patches.
Abstract: In this letter, a new design for single-feed dual-band circularly polarized microstrip antennas is presented. A stacked- patch configuration is used for the antenna, and circular polarization is achieved by designing asymmetrical U-slots on the patches. The dimensions of the U-slots are optimized to achieve circular polarization in both bands. A prototype has been designed to operate at two frequencies with a ratio of 1.66. Both experimental and theoretical results are presented and discussed. The circularly polarized bandwidth of the antenna is 1.0% at 3.5 GHz (WiMax) and 3.1% at 5.8 GHz (HiperLAN).
TL;DR: In this article, a microstrip diplexer with a joint T-shaped resonator was proposed for high isolation and wide stopband in addition to satisfying the passband requirement.
Abstract: This study presents a novel microstrip diplexer with a joint T-shaped resonator. The T-shaped resonator has an extremely small frequency ratio using microstrip with practical line width. Additionally, the T-shaped resonator can be used as a frequency selective signal splitter, making it feasible to design a diplexer for a system with two extremely close bands. The diplexer using a joint T-shaped resonator does not require combining circuits and matching networks. A diplexer used in the UMTS-WCDMA system is designed and measured. The proposed diplexer has high isolation and wide stopband in addition to satisfying the passband requirement. A satisfactory agreement between the simulated results and the measured results validate the proposed configuration.
TL;DR: In this paper, a simple, low-cost, and compact printed dual-band fork-shaped monopole antenna for Bluetooth and ultrawideband (UWB) applications is proposed.
Abstract: A simple, low-cost, and compact printed dual-band fork-shaped monopole antenna for Bluetooth and ultrawideband (UWB) applications is proposed. Dual-band operation covering 2.4-2.484 GHz (Bluetooth) and 3.1-10.6 GHz (UWB) frequency bands are obtained by using a fork-shaped radiating patch and a rectangular ground patch. The proposed antenna is fed by a 50-Ω microstrip line and fabricated on a low-cost FR4 substrate having dimensions 42 (Lsub) × 24 (Wsub) × 1.6 (H) mm3. The antenna structure is fabricated and tested. Measured S11 is ≤ -10 dB over 2.3-2.5 and 3.1-12 GHz. The antenna shows acceptable gain flatness with nearly omnidirectional radiation patterns over both Bluetooth and UWB bands.
Patent•
19 Apr 2011
TL;DR: The dual-polarized microstrip antenna of multi-layer radiation structure is designed in a relatively small volume, which effectively saves the cost of antenna installation and maintenance, and is widely applied in the fields of mobile communication and internet technology as discussed by the authors.
Abstract: A dual-polarized microstrip antenna includes: at least one metal radiating patch, i.e. a first metal radiating patch; at least one ground metal layer whereon excitation micro-slots are etched; at least one dielectric layer, i.e. a first dielectric layer it is preferred that the dielectric layer is a resonant dielectric layer such as a resonant dielectric layer of air or other layers of optimization resonant materials; at least one set of bipolar excitation microstrip lines; the dielectric layer is between the first metal radiating patch and the ground metal layer. The dual-polarized microstrip antenna of multi-layer radiation structure is designed in a relatively small volume, which effectively saves the cost of antenna installation and maintenance, and is widely applied in the fields of mobile communication and internet technology.
TL;DR: In this paper, a triple-band bandpass filter with two transmission poles in each passband is proposed using three pairs of degenerate modes in a ring resonator, where four open-circuited stubs are attached symmetrically along the ring and they are treated as perturbation elements to split the two second-order degenerate mode, resulting in a two-pole second passband.
Abstract: In this paper, a class of triple-band bandpass filters with two transmission poles in each passband is proposed using three pairs of degenerate modes in a ring resonator. In order to provide a physical insight into the resonance movements, the equivalent lumped circuits are firstly developed, where two transmission poles in the first and third passbands can be distinctly tracked as a function of port separation angle. Under the choice of 135° and 45° port separations along a ring, four open-circuited stubs are attached symmetrically along the ring and they are treated as perturbation elements to split the two second-order degenerate modes, resulting in a two-pole second passband. To verify the proposed design concept, two filter prototypes on a single microstrip ring resonator are finally designed, fabricated, and measured. The three pairs of transmission poles are achieved in all three passbands, as demonstrated and verified in simulated and measured results.
TL;DR: In this paper, the impedance matching of the classic printed circular disc UWB monopole is improved by introducing transitions between the microstrip feed line and the printed disc and two particular designs are examined using a dual and single microstrip transition.
Abstract: Circular disc monopole antennas are investigated for current and future ultrawideband (UWB) applications. The studied antennas are compact and of small size (25 mm × 35 mm × 0.83 mm) with a 50-Ω feed line and offer a very simple geometry suitable for low cost fabrication and straightforward printed circuit board integration. More specifically, the impedance matching of the classic printed circular disc UWB monopole is improved by introducing transitions between the microstrip feed line and the printed disc. Two particular designs are examined using a dual and single microstrip transition. By using this simple antenna matching technique, respective impedance bandwidths (|Sn | <; -10 dB) from 2.5 to 11.7 GHz and 3.5 to 31.9 GHz are obtained. Results are also compared to a classic UWB monopole with no such matching network transitions. Measured and simulated reflection coefficient curves are provided along with beam patterns, gain and group delay values as a function of frequency. The transient behavior of the studied antennas is also examined in the time domain.
TL;DR: In this paper, a novel and compact composite right/left-handed (CRLH) quarter-wave type resonators are proposed, which can resonate at the frequency where the electrical length is phase-leading or negative, which results in a smaller size as compared to the conventional phase-delayed microstrip-line resonator.
Abstract: Novel and compact composite right/left-handed (CRLH) quarter-wave type resonators are proposed in this paper. The resonator can resonate at the frequency where the electrical length is phase-leading or negative, which results in a smaller size as compared to the conventional phase-delayed microstrip-line resonator. Furthermore, it is only half the size of the CRLH half-wave resonator resonating at the same frequency. In addition, the proposed resonator is capable of engineering the multiresonances very close to each other, which makes it suitable to implement the miniaturized multiband microwave components such as diplexers and triplexers. A very compact diplexer and a very compact triplexer are proposed based on the proposed CRLH quarter-wave resonators in this paper and both of them have demonstrated very good performance. Specifically, compared to the referenced works based on the conventional microstrip resonators, the proposed diplexer and triplexer are 50% and 76% smaller than their microstrip counterparts, respectively.
TL;DR: In this article, the gain of low temperature co-fired ceramic (LTCC) patch antenna arrays operating at 60 GHz is enhanced by introducing open air cavities around their radiating patches.
Abstract: The gain of low temperature co-fired ceramic (LTCC) patch antenna arrays operating at 60 GHz is enhanced by introducing open air cavities around their radiating patches. The open air cavities reduce the losses caused by severe surface waves and dielectric substrate at millimeter-wave (mmW) bands. The arrays are excited through either a microstrip-line or stripline feed network with a grounded coplanar-waveguide (GCPW) transition. The GCPW transition is designed so that the antenna can be measured with the patch array facing free space therefore reducing the effect of the probe station on the measurement. The proposed antenna arrays with the open air cavities achieves gain enhancement of 1-2 dB compared to the conventional antenna array without any open air cavity across the impedance bandwidth of about 7 GHz for |S11| ≤ - 10 dB at 60-GHz band.
TL;DR: A set of external tuning circuits were designed to demonstrate the potential of the proposed configuration for applications where some level of reconfigurability is required and to improve the isolation between the wideband and narrowband ports several modified arrangements were presented and investigated.
Abstract: An integration concept for multi-standard antennas is described. This technique is based on utilizing a relatively large antenna that is printed on the top side of a substrate, acting as a ground for a smaller antenna. The smaller antenna is printed onto the bottom side of the substrate. To validate this concept, an integrated wide-narrowband demonstrator antenna is presented. This antenna is composed of a shorted microstrip patch integrated with a coplanar waveguide (CPW) fed ultrawideband (UWB) antenna. A prototype of the integrated antenna was fabricated and its performance was verified. This arrangement is a promising candidate for applications where some level of reconfigurability is required. For this reason, a set of external tuning circuits were designed to demonstrate the potential of the proposed configuration for such applications. In order to improve the isolation between the wideband and narrowband ports several modified arrangements were presented and investigated.
TL;DR: In this article, a simple microstrip ring-resonator is presented for novel design of dual-band dual-mode bandpass filters with good isolation and upper-stopband performance.
Abstract: A simple microstrip ring-resonator is presented for novel design of dual-band dual-mode bandpass filters with good isolation and upper-stopband performance. By increasing the length of the loaded open-circuited stub, the two first-order degenerate modes are excited and slit for the use of the first passband, while one of the third-order degenerate modes moves downward and forms the second passband together with a second-order degenerate mode. Meanwhile, three transmission zeros are properly tuned for the rejections between the two passbands and in the upper stopband. After installing two coupled-line sections on a square ring at the two ports with 90°-separation, a dual-band filter with the two transmission poles in each passband is designed and measured. Without adding any additional perturbation element inside the ring, the measured filter shows good performance for both in-band matching and outside rejections of the desired dual passbands.
TL;DR: In this article, a planar diplexer based on the substrate integrated waveguide (SIW) with complementary split-ring resonators (CSRRs) etched on the waveguide surface is developed.
Abstract: A novel high-performance planar diplexer is developed based on the substrate integrated waveguide (SIW) with complementary split-ring resonators (CSRRs) etched on the waveguide surface. The proposed diplexer is operated below the characteristic cutoff frequency of the waveguide. The filtering response of the SIW-CSRR combined structure is investigated first. The diplexer is then implemented based on two cascaded two-pole bandpass filters. Equivalent circuit, simulated results and experimental verification are all provided. This diplexer shows advantages in terms of the compact size, low loss, high isolation, easy fabrication and integration with other circuits.
TL;DR: In this paper, an open loop notch band resonator is used to separate the resonator from the antenna, which can now be designed in isolation, using the standard approach described in the literature, and then combined.
Abstract: Ultrawideband (UWB) systems require band notch filters in order to prevent sensitive components, within the front-end of the receiver, from being overloaded by strong signals. Recently, it has been shown that these filters can be integrated into the UWB antenna, to great advantage. This communication presents a new method for forming a notch band within the frequency response of a UWB antenna. An open loop notch band resonator is located on the back of the substrate, used to support the UWB monopole. The act of separating the resonator from the antenna means that they can now be designed in isolation, using the standard approach described in the literature, and then combined. A prototype was constructed and good agreement has been obtained between simulation and measurement. The radiation patterns are consistent over the frequency range of interest.
TL;DR: In this article, a modified bow-tie antenna with reduced metallization was designed and fabricated at the Flexible Display Center (FDC) of Arizona State University (ASU).
Abstract: Design, simulation, fabrication and measurement of two different novel flexible bow-tie antennas, a conventional and a modified bow-tie antenna with reduced metallization, are reported in this paper. The antennas are mounted on a flexible substrate fabricated at the Flexible Display Center (FDC) of Arizona State University (ASU). The substrate is heat stabilized polyethylene naphthalate (PEN) which allows the antennas to be flexible. The antennas are fed by a microstrip-to-coplanar feed network balun. The reduction of the metallization is based on the observation that the majority of the current density is confined towards the edges of the regular bow-tie antenna. Hence, the centers of the triangular parts of the conventional bow-tie antenna are removed without compromising significantly its performance. The return losses and radiation patterns of the antennas are simulated with HFSS and the results are compared with measurements, for bow-tie elements mounted on flat and curved surfaces. The comparisons show that there is an excellent agreement between the simulations and measurements for both cases. Furthermore, the radiation performance of the modified bow-tie antenna is verified, by simulations and measurements, to be very close to the conventional bow-tie.
TL;DR: In this article, the branch-line coupler can be extended by suitably incorporating additional sections into the composite design to achieve better return loss and isolation of the three-and four-section couplers.
Abstract: The branch-line coupler may be redesigned for crossover application. The bandwidth of such a coupler can be extended by suitably incorporating additional sections into the composite design. Laboratory tests on microstrip prototypes have shown the return loss and isolation of the three- and four-section couplers to be better than 20 dB over bandwidths of 22% and 33%, respectively. The insertion losses and group delays vary by less than ±0.05 dB and ±1 ns, respectively, for both prototypes.
TL;DR: In this paper, two circular-polarized circular patch antennas which have novel feeding structures such as a substrate integrated waveguide (SIW), a cavity-backed resonator and two different feeding transitions, are proposed and experimentally investigated in terms of electrical performances, including reflection coefficients, optimized parameter values, circular polarized antenna gain, axial ratios and radiation patterns.
Abstract: Two circular-polarized circular patch antennas which have novel feeding structures such as a substrate integrated waveguide (SIW), a cavity-backed resonator and two different feeding transitions, are proposed and experimentally investigated in terms of electrical performances, including reflection coefficients, optimized parameter values, circular polarized antenna gain, axial ratios and radiation patterns. By inserting asymmetrical inductive via arrays into the interface region between the circular patch and SIW feeding structure, it is found that an enhancement of input impedance bandwidth has been achieved. In addition, in order to check the effects of feeding transition types on the electrical performances of the main radiator, two different feeding transitions, namely microstrip-to-SIW and coax-to-SIW, have been studied by considering reflection coefficients, gain, axial ratios and radiation patterns. As a result, it is experimentally proved that a broadband impedance bandwidth of 17.32% and 14.42% under the criteria of less than VSWR 2:1 and 1.5:1, respectively, have been obtained and an RHCP axial ratio of 2.34% with a maximum gain of 7.79 dBic has been accomplished by using the proposed antenna with coax-to-SIW transition operating at the X-band of 10 GHz center frequency.
TL;DR: In this paper, a simple microstrip fed folded strip monopole antenna (FSMA) with a protruding stub in the ground plane for the application in WLAN and RFID is presented.
Abstract: The design of a simple microstrip fed folded strip monopole antenna (FSMA) with a protruding stub in the ground plane for the application in WLAN and RFID is presented. The antenna has two resonant paths, one in the radiating element (folded strip) and the other in the protruding stub of the ground plane. It supports two resonances at 2.4 GHz and 5.81 GHz, which are the center frequencies of WLAN and RFID. Effectively consistent radiation pattern and large percentage bandwidth have been observed. The measured percentage fractional bandwidth at 2.4 GHz (2.05 GHz to 2.86 GHz) is 32.99, and the percentage fractional bandwidth at 5.81 GHz (5.55 GHz to 6.14GHz) is 10.11. The proposed antenna is simple and compact in size, providing broadband impedance matching, consistent radiation pattern and appropriate gain characteristics in the WLAN and RFID frequency regions.
TL;DR: In this paper, the authors presented a novel -band wideband circularly polarized 64-element microstrip antenna array with double application of the sequential rotation feeding technique, which can find good applications in aerospace, radar, and communication systems.
Abstract: A novel -band wideband circularly polarized 64-element microstrip antenna array is presented in this letter. It is developed with double application of the sequential rotation feeding technique. The array employs corner-truncated microstrip patches as the basic element, and then a four-element array as the subarray. By applying the sequential rotation technique twice to design the feed networks, a full 64-element array with good performance is obtained. A prototype of the full array was constructed and tested. The measurement results show that both the reflection coefficient of less than 10 dB and axial ratio of less than 3 dB have been achieved over a frequency band of 27-31 GHz; this corresponds to a wide bandwidth of 13.8%. Due to its planar configuration, the proposed array can find good applications in aerospace, radar, and communication systems.
TL;DR: In this paper, a procedure is developed to predict electromagnetic interference from electronic products using near-field scan data, which is used to define equivalent electric and magnetic current sources characterizing the electromagnetic emissions from an electronic circuit.
Abstract: A procedure is developed to predict electromagnetic interference from electronic products using near-field scan data. Measured near-field data are used to define equivalent electric and magnetic current sources characterizing the electromagnetic emissions from an electronic circuit. Reconciliation of the equivalent sources is performed to allow the sources to be accurately applied within full-wave numerical modeling tools like finite-difference time domain (FDTD). Results show that the radiated fields must typically be represented by both electric and magnetic current sources if scattering and multiple-reflections from nearby objects are to be taken into account. The accuracy of the approach is demonstrated by predicting the fields generated by a microstrip trace within and outside of a slotted enclosure, and by predicting the fields generated by the microstrip trace close to a long wire. Values predicted from near-field scan data match those from full-wave simulations or measurements within 6 dB.