Showing papers on "Microstrip published in 2013"

Metamaterials with Negative Parameters: Theory, Design, and Microwave Applications

Abstract: Dedicatory. Acknowledgements. Preface. 1. The electrodynamics of left-handed media. 1.1. Wave propagation in left-handed media. 1.2. Energy density and group velocity. 1.3. Negative refraction. 1.4. Fermat principle. 1.5. Other effects in left-handed media. 1.5.1. Inverse Doppler effect. 1.5.2. Backward Cerenkov radiation. 1.5.3. Negative Goos-Hanchen shift. 1.6. Waves at interfaces. 1.6.1. Transmission and reflection coefficients. 1.6.2. Surface waves. 1.7. Waves through left-handed slabs. 1.7.1. Transmission and reflection coefficients. 1.7.2. Guided waves. 1.7.3. Backward leaky and complex waves. 1.8. Slabs with epsilon/epsilon o -1 and / o -1. 1.8.1. Phase compensation and amplification of evanescent modes. 1.8.2. Perfect tunneling. 1.8.3. The perfect lens. 1.8.4. The perfect-lens as a tunneling/matching device. 1.9. Losses and dispersion. 1.10. Indefinite media. 1.11. Problems. References. 2. Synthesis of bulk metamaterials. 2.1. Scaling plasmas at microwave frequencies. 2.1.1. Metallic waveguides and plates as one- and two-dimensional plasmas. 2.1.2. Wire media. 2.1.3. Spatial dispersion in wire media. 2.2. Synthesis of negative magnetic permeability. 2.2.1. Analysis of the edge-coupled SRR. 2.2.2. Other SRR designs. The broadside-coupled SRR. The non-bianisotropic SRR. The double split SRR. Spirals. 2.2.3. Constitutive relationships for bulk SRR metamaterials. 2.2.4. Higher order resonances in SRRs. 2.2.5. Isotropic SRRs. 2.2.6. Scaling down SRRs to infrared and optical frequencies. 2.3. SRR-based left-handed metamaterials. 2.3.1. One-dimensional SRR-based left-handed metamaterials. 2.3.2. Two-dimensional and three-dimensional SRR-based lefthanded metamaterials. 2.3.3. On the application of the continuous medium approach to discrete SRR-based left-handed metamaterials. 2.3.4. The ?superposition? hypothesis. 2.3.5. On the numerical accuracy of the developed model for SRR-based metamaterials. 2.4. Other approaches to bulk metamaterial design. 2.4.1. Ferrite metamaterials. 2.4.2. Chiral metamaterials. 2.4.3. Other proposals. 2.5. Appendix. 2.6. Problems. References. 3. Synthesis of metamaterials in planar technology. 3.1. The dual (backward) transmission line concept. 3.2. Practical implementation of backward transmission lines. 3.3. Two-dimensional (2D) planar metamaterials. 3.4. Design of left handed transmission lines by means of SRRs: the resonant type approach. 3.4.1. Effective negative permeability transmission lines. 3.4.2. Left handed transmission lines in microstrip and CPW technologies. 3.4.3. Size reduction. 3.5. Equivalent circuit models for SRRs coupled to conventional transmission lines. 3.5.1. Dispersion diagrams. 3.5.2. Implications of the model. 3.6. Duality and complementary split rings resonators (CSRRs). 3.6.1. Electromagnetic properties of CSRRs. 3.6.2. Numerical calculation and experimental validation. 3.7. Synthesis of metamaterial transmission lines by using CSRRs. 3.7.1. Negative permittivity and left handed transmission lines. 3.7.2. Equivalent circuit models for CSRR loaded transmission lines. 3.7.3. Parameter extraction. 3.7.4. Effects of cell geometry on frequency response. 3.8. Comparison between the circuit models of resonant type and dual left handed lines. Problems. References. 4. Microwave applications of metamaterial concepts. 4.1. Filters and diplexers. 4.1.1. Stop band filters. 4.1.2. Planar filters with improved stop band. 4.1.3. Narrow band pass filter and diplexer design. 4.1.3.1. Band pass filters based on alternate right/left handed (ARLH) sections implemented by means of SRRs. 4.1.3.2. Band pass filters and diplexers based on alternate right/left handed (ARLH) sections implemented by means of CSRRs. 4.1.4. CSRR-based band pass filters with controllable characteristics. 4.1.4.1. Band pass filters based on the hybrid approach: design methodology and illustrative examples. 4.1.4.2. Other CSRR-based filters implemented by means of right handed sections. 4.1.5. High pass filters and ultra wide band pass filters (UWBPFs) implemented by means of resonant type balanced CRLH metamaterial transmission lines. 4.1.6. Tunable filters based on varactor-loaded split rings resonators (VLSRRs). 4.1.6.1. Topology of the VLSRR and equivalent circuit model. 4.1.6.2. Validation of the model. 4.1.6.3. Some illustrative results: tunable notch filters and stop band filters. 4.2. Synthesis of metamaterial transmission lines with controllable characteristics and applications. 4.2.1. Miniaturization of microwave components. 4.2.2. Compact broadband devices. 4.2.3. Dual band components. 4.2.4. Coupled line couplers. 4.3. Antenna applications. Problems. References. 5. Advanced and related topics. 5.1. SRR and CSRR based admittance surfaces. 5.1.1. Babinet principle for a single split rings resonator. 5.1.2. Surface admittance approach for SRR planar arrays. 5.1.3. Babinet principle for CSRR planar arrays. 5.1.4. Behavior at normal incidence. 5.1.5. Behavior at general incidence. 5.2. Magneto- and electro-inductive waves. 5.2.1. The magneto-inductive wave equation. 5.2.2. Magneto-inductive surfaces. 5.2.3. Electro-inductive waves in CSRR arrays. 5.2.4. Applications of magneto- and electro-inductive waves. 5.3. Sub-diffraction imaging devices. 5.3.1. Some universal features of sub-diffraction imaging devices. 5.3.2. Imaging in the quasi-electrostatic limit. Role of surface plasmons. 5.3.3. Imaging in the quasi-magnetostatic limit. Role of magnetostatic surface waves. 5.3.4. Imaging by resonant impedance surfaces. Magneto-inductive lenses. 5.3.5. Canalization devices. 5.4. Problems. References.

Microstrip Patch Antennas: A Designer's Guide

Abstract: Acknowledgements. 1: Introduction R. Waterhouse. 1.1. History. 1.2. Advantages and Issues. 1.3. Applications. 1.4. Summary of Book. 1.5. Bibliography. 2: Fundamental Properties of Single Layer Microstrip Patch Antennas R. Waterhouse, D. Novak, D.-K. Park, Y. Qian, T. Itoh. 2.1. Introduction. 2.2. General Theory of Operation and Design Tools. 2.3. The Effect of Conductor Shape. 2.4. Impedance and Radiation Performance of Single Layer Patches. 2.5. Excitation Methods of Microstrip Patches. 2.6. Circular Polarization Generation. 2.7. Summary. 2.8. Bibliography. 3: Enhancing the Bandwidth of Microstrip Patch Antennas R. Waterhouse, J.T. Aberle, D. M. Kokotoff, A. Mitchell, M. Lech, S.D. Targonski, M. Lye, F. Zavosh, K. Ghorbani, D. Novak, A. Nirmalathas, C. Lim. 3.1. Introduction. 3.2. Intuitive Procedures. 3.3. Horizontally Coupled Parasitic Patches. 3.4. Stacked Patches. 3.5. Large Slot Excited Patches. 3.6. Aperture Stacked Patches. 3.7. Ultra-wideband ASPs. 3.8. Summary. 3.9. Bibliography. 4: Improving the Efficiency of Microstrip Patch Antennas R. Waterhouse, D. Pavlickovski, D. M. Kokotoff, J.T. Aberle. 4.1. Introduction. 4.2. Surface Waves. 4.3. Patches that do not Excite TM Surface Waves. 4.4. Hi-lo Stacked Patches. 4.5. Photonic Band-gap Structures. 4.6. Summary. 4.7. Bibliography. 5: Small Microstrip Patch Antennas R. Waterhouse, H.K. Kan, D.M. Kokotoff, S.D. Targonski, J.T. Rowley, D. Pavlickovski. 5.1. Introduction. 5.2. Shorted Microstrip Patches. 5.3. Further Size Reduction Techniques for Shorted Patches. 5.4. Winged Shorted Patch. 5.5. Shorted Spiral Patches. 5.6. Improving the Performances of Shorted Microstrip Patches. 5.7. Performance of Shorted Microstrip Patch Antennas for Mobile Communications Handsets at 1800 MHz. 5.8. Summary. 5.9. Bibliography. 6: Direct Integration of Microstrip Antennas R. Waterhouse, W.S.T. Rowe, D. Novak, A. Nirmalathas, C. Lim. 6.1. Overview for Requirernents for Integration. 6.2. Slot Coupled Procedures and Solutions. 6.3. Direct Contact Procedures and Solutions. 6.4. Summary. 6.5. Bibliography. 7: Microstrip Patch Arrays R. Waterhouse, K. Ghorbani, W.S.T. Rowe, S.D. Targonski, L. Mali, H.K. Kan, D. Novak, A. Nirmalathas, C. Lim. 7.1. Introduction. 7.2. Series Fed Arrays. 7.3. Parallel Fed Arrays. 7.4. Combination Fed Arrays. 7.5. Large Scanned Arrays of Microstrip Patches. 7.6. Alternatives to Large Arrays of Microstrip Patches. 7.7. Wraparound Patch Antenna Arrays. 7.8. Summary. 7.9. Bibliography. 8: Summary R. Waterhouse. 8.1. Overview. 8.2. Future Directions of Microstrip Patch Technology. 8.3. Bibliography. List of Contributors.

Interchip communication using a dielectric waveguide

Abstract: An apparatus is provided. There is a circuit assembly (206-A1) with a package substrate (304-A) and an integrated circuit (IC) (302-A). The package substrate has a microstrip line (208-A1), and the IC is secured to the package substrate and is electrically coupled to the microstrip line. A circuit board (202-A) is also secured to the package substrate. A dielectric waveguide (204- A) is secured to the circuit board. The dielectric waveguide has a dielectric core (310-A) that extends into a transition region (314- A) located between the dielectric waveguide and the microstrip line, and the microstrip line is configured to form a communication link with the dielectric waveguide.

Implementation of Slotted Meander-Line Resonators for Isolation Enhancement in Microstrip Patch Antenna Arrays

Abstract: A new approach to enhance the isolation in microstrip patch antenna arrays is described in this letter. The implementation of a slotted meander-line resonator (SMLR) is done by creating defect in the microstrip structure particularly designed for band-notch function. The resonator is designed to block the surface current at the resonant frequency of the two patch antennas coupled along H-plane and operating at a frequency of 4.8 GHz. The interelement isolation before and after the implementation of SMLR has been investigated. The proposed configuration provides an improvement in isolation by 16 dB (measured value) with a reduced edge-to-edge spacing of 7 mm $(\lambda_{o}/9)$ . The configuration has been designed, simulated, and validated experimentally.

RF system-in-package with microstrip-to-waveguide transition

Abstract: An apparatus includes an IC package comprising a substrate having a first metal layer, a second metal layer, and a dielectric layer disposed between the first and second metal layers. The IC package further comprises an IC die disposed at a surface of the substrate and comprising RF circuitry. The first metal layer comprises a microstrip feedline extending from a pin of the IC die. The microstrip feedline includes a conductive trace having a probe element at a tip distal from the pin. The first metal layer further comprises a waveguide opening comprising a region surrounding the probe element, the region being substantially devoid of conductive material. The substrate further comprises a plurality of metal vias disposed at the perimeter of the region, the metal vias extending from the first metal layer to the second metal layer.

Compact Microstrip Dual-/Tri-/Quad-Band Bandpass Filter Using Open Stubs Loaded Shorted Stepped-Impedance Resonator

Abstract: This paper presents a new class of dual-, tri- and quad-band BPF by using proposed open stub-loaded shorted stepped-impedance resonator (OSLSSIR). The OSLSSIR consists of a two-end-shorted three-section stepped-impedance resistor (SIR) with two identical open stubs loaded at its impedance junctions. Two 50- Ω tapped lines are directly connected to two shorted sections of the SIR to serve as I/O ports. As the electrical lengths of two identical open stubs increase, many more transmission poles (TPs) and transmission zeros (TZs) can be shifted or excited within the interested frequency range. The TZs introduced by open stubs divide the TPs into multiple groups, which can be applied to design a multiple-band bandpass filter (BPF). In order to increase many more design freedoms for tuning filter performance, a high-impedance open stub and the narrow/broad side coupling are introduced as perturbations in all filters design, which can tune the even- and odd-mode TPs separately. In addition, two branches of I/O coupling and open stub-loaded shorted microstrip line are employed in tri- and quad-band BPF design. As examples, two dual-wideband BPFs, one tri-band BPF, and one quad-band BPF have been successfully developed. The fabricated four BPFs have merits of compact sizes, low insertion losses, and high band-to-band isolations. The measured results are in good agreement with the full-wave simulated results.

Experimental demonstration of reflectarray antennas at terahertz frequencies

Abstract: Reflectarrays composed of resonant microstrip gold patches on a dielectric substrate are demonstrated for operation at terahertz frequencies. Based on the relation between the patch size and the reflection phase, a progressive phase distribution is implemented on the patch array to create a reflector able to deflect an incident beam towards a predefined angle off the specular direction. In order to confirm the validity of the design, a set of reflectarrays each with periodically distributed 360 × 360 patch elements are fabricated and measured. The experimental results obtained through terahertz time-domain spectroscopy (THz-TDS) show that up to nearly 80% of the incident amplitude is deflected into the desired direction at an operation frequency close to 1 THz. The radiation patterns of the reflectarray in TM and TE polarizations are also obtained at different frequencies. This work presents an attractive concept for developing components able to efficiently manipulate terahertz radiation for emerging terahertz communications.

A Reconfigurable Triple-Notch-Band Antenna Integrated with Defected Microstrip Structure Band-Stop Filter for Ultra-Wideband Cognitive Radio Applications

Abstract: A printed reconfigurable ultra-wideband (UWB) monopole antenna with triple narrow band-notched characteristics is proposed for cognitive radio applications in this paper. The triple narrow band-notched frequencies are obtained using a defected microstrip structure (DMS) band stop filter (BSF) embedded in the microstrip feed line and an inverted π-shaped slot etched in the rectangular radiation patch, respectively. Reconfigurable characteristics of the proposed cognitive radio antenna (CRA) are achieved by means of four ideal switches integrated on the DMS-BSF and the inverted π-shaped slot. The proposed UWB CRA can work at eight modes by controlling switches ON and OFF. Moreover, impedance bandwidth, design procedures, and radiation patterns are presented for analysis and explanation of this antenna. The designed antenna operates over the frequency band between 3.1 GHz and 14 GHz (bandwidth of 127.5%), with three notched bands from 4.2 GHz to 6.2 GHz (38.5%), 6.6 GHz to 7.0 GHz (6%), and 12.2 GHz to 14 GHz (13.7%). The antenna is successfully simulated, fabricated, and measured. The results show that it has wide impedance bandwidth, multimodes characteristics, stable gain, and omnidirectional radiation patterns.

Compact Microstrip Wilkinson Power Dividers With Harmonic Suppression and Arbitrary Power Division Ratios

Abstract: This paper describes a new Wilkinson power divider on a single-layer microstrip line that can reduce the occupied area, suppress the harmonic components, and/or provide the arbitrary power division ratios. It consists of two-section transmission lines, two inductors, and one isolation resistor. Four different designs have been conducted to investigate the capabilities of the structure. In addition, a compact divider along with harmonic suppression and a practical divider with a large power-dividing ratio has been constructed and measured. The simulation and measurement results are in good agreement with each other. This indicates that the structure can effectively be used as a power divider for miniaturized or arbitrary power division ratio applications.

A Novel Compact Printed Rectenna for Data Communication Systems

Abstract: A novel design of a two-port printed microstrip rectenna with compact structure for communication systems is presented An aperture-coupled dual polarization patch antenna is utilized as the receiving antenna The vertical feed port receives the microwave energy and transfers it to the rectifying circuit for dc power generation, while the horizontal feed port is used for data communication, with high isolation between the two ports This patch antenna includes harmonic suppression functionality, which is essential for high microwave—direct current (mw-dc) conversion efficiency A co-simulation procedure using HFSS and ADS for the analysis of the rectenna and the rectifying circuit design is used This design assumes low input power for the rectifying circuit to comply with safety standards A mw-dc conversion efficient of 63% is measured with a 900 $\Omega$ load, 578 GHz operation frequency, and 25 mW receiving power For the communication port, the measured reflection coefficient is $-$ 18 dB at 61 GHz center frequency, the gain is 70 dBi, and the cross polarization in the broadside direction is $-$ 15 dB

Three-Dimensional Bandpass Frequency-Selective Structures With Multiple Transmission Zeros

Abstract: A new class of three-dimensional (3-D) bandpass frequency-selective structures (FSSs) with multiple transmission zeros is presented to realize wide out-of-band rejection. The proposed FSSs are based on a two-dimensional (2-D) array of shielded microstrip lines with shorting via to ground, where two different resonators in the substrate are constructed based on the excited substrate mode. Furthermore, metallic plates of rectangular shape and “T-type” are inserted in the air region of shielded microstrip lines, which can introduce additional resonators provided by the air mode. Using this arrangement, a passband with two transmission poles can be obtained. Moreover, multiple transmission zeros outside the passband are produced for improving the out-of-band rejection. The operating principles of these FSSs are explained with the aid of equivalent circuit models. Two examples are designed, fabricated, and measured to verify the proposed structures and circuit models. Measured results demonstrate that the FSSs exhibit high out-of-band rejection and stable filtering response under a large variation of the incidence angle.

Design of Miniaturized Filtering Power Dividers for System-in-a-Package

Abstract: Miniaturized power dividers with high-selectivity bandpass behavior are presented and analyzed theoretically in this paper. Based on the coupled-resonator topology, the circuit area of the proposed power divider can be reduced as the size of the assembled resonators shrinks. Therefore, in order to effectively reduce the circuit area and improve the stopband performance, the net-type resonator is selected to design the filtering power dividers. For demonstration, power dividers with Chebyshev- and quasi-elliptic bandpass responses have been designed and fabricated with microstrip in printed circuit boards. The highly symmetric structure of each power divider provides a low in-band magnitude and phase imbalances. Consequently, the proposed filtering power dividers have advantages of small size, sharp skirt selectivity, high isolation, and superior out-of-band performance. All measured results are in good agreement with the full-wave simulation results.

Compact Multi-Band H-Shaped Slot Antenna

Abstract: A compact triple-band H-shaped slot antenna fed by microstrip coupling is proposed. Four resonant modes are excited, including a monopole mode, a slot mode, and their higher-order modes, to cover GPS (1.575 GHz) and Wi-Fi (2.4-2.485 GHz and 5.15-5.85 GHz), respectively. Sensitivity study of the slot geometry upon the resonant modes have been conducted. The measured gains at these four resonant frequencies are 0.2 dBi, 3.5 dBi, 2.37 dBi, and 3.7 dBi, respectively, and the total efficiencies are -2.5 dB, -1.07 dB, -3.06 dB, and -2.7 dB, respectively. The size of this slot antenna is only 0.24λ0×0.034λ0, where λ0 is the free-space wavelength at 1.575 GHz, hence is suitable to install on notebook PC's and handheld devices.

Compact Printed Wide-Slot UWB Antenna With 3.5/5.5-GHz Dual Band-Notched Characteristics

Abstract: A novel compact wide-slot ultrawideband (UWB) antenna with dual band-notched characteristics is presented. The antenna consists of an inverted U-shaped slot on the ground plane and a radiation patch similar to the slot that is fed by a 50-Ω microstrip line. By etching a C-shaped slot on the radiation patch and extruding an L-shaped stub from the ground plane, dual band-notched properties in the WiMAX (3.4-3.69 GHz) and WLAN (5.15-5.825 GHz) are achieved. The proposed antenna has a compact size of 20×27 mm2 and operates from 2.89 to 11.52 GHz. Furthermore, nearly omnidirectional radiation patterns and constant gain are obtained in the working band.

Comparative Study of Antenna Designs for RF Energy Harvesting

Abstract: In the last few years, several antenna designs of rectenna that meet various objectives have been proposed for use in RF energy harvesting. Among various antennas, microstrip patch antennas are widely used because of their low profile, light weight, and planar structure. Conventional patch antennas are rectangular or circular in shape, but variations in their basic design are made for different purposes. This paper begins with an explanation and discussion of different designs, put forward with an aim of miniaturization, harmonic rejection, and reconfigurability. Finally, microstrip patch structured rectennas are evaluated and compared with an emphasis on the various methods adopted to obtain a compact rectenna, harmonic rejection functionality, and frequency and polarization selectivity.

Electrical Tunable Microstrip LC Bandpass Filters With Constant Bandwidth

Abstract: In this paper, two- and three-pole microstrip LC constant fractional bandwidth (CFBW) and constant absolute bandwidth (CABW) tunable bandpass filters are proposed. The equivalent-circuit models are presented to study the tunable mechanism. The filter can be reconfigured by changing the capacitance of the LC resonators. Based on electric coupling coefficient compensation, second- and third-order tunable equivalent-circuit models with CFBW/CABW are presented. For demonstration, a semiconductor varactor diode loaded microstrip LC resonator is adopted in our work to design the second- and third-order tunable filters. The S-parameters, group delays, and third-order intercept points for different center frequencies of the filters are presented. Each resonator requires only one varactor diode for both central frequency and resonator coupling coefficient control.

A Self-Adapting Flexible (SELFLEX) Antenna Array for Changing Conformal Surface Applications

Abstract: A phased-array test platform for studying the self-adapting capabilities of conformal antennas is developed and presented. Specifically, a four-port 2.45-GHz receiver with voltage controlled phase shifters and attenuators is designed along with four individual printed microstrip patch antennas attached to a conformal surface. Each antenna is connected to the corresponding receiver port with a flexible SMA cable. It is shown that with appropriate phase compensation, the distorted radiation pattern of the array can be recovered as the surface of the conformal array changes shape. This pattern recovery information is then used to develop a new self-adapting flexible 1 t 4 microstrip antenna array with an embedded flexible sensor system. In particular, a flexible resistive sensor is used to measure the deformation of the substrate of a conformal antenna array, while a sensor circuit is used to measure the changing resistance. The circuit then uses this information to control the individual voltage of the phase shifters of each radiating element in the array. It is shown that with appropriate phase compensation, the radiation properties of the array can be autonomously recovered as the surface of the flexible array changes shape during normal operation. Throughout this work, measurements are shown to agree with analytical solutions and simulations.

Control of Higher Harmonics and Their Radiations in Microstrip Antennas Using Compact Defected Ground Structures

Abstract: Controlling higher order modes up to third harmonic of the fundamental operating frequency in a microstrip line-fed patch antenna has been successfully demonstrated. Harmonic rejection in the antenna has been achieved at its feed level using highly compact design of defected ground structure (DGS). Rejection characteristics have been improved adding an open stub to the feed line. All possible higher order modes occurring in between the fundamental and the 3rd harmonic have been identified. Relative suppression of radiated fields with and without DGS-control has been quantitatively measured and effective control of harmonics has been experimentally ensured. The area occupied by the proposed DGS has been compared with earlier designs and over 40-90% reduction in size has been documented.

A Balanced-to-Balanced Power Divider With Arbitrary Power Division

Abstract: In this paper, a balanced-to-balanced power divider is proposed, for the first time, with arbitrary power division, which can be regarded as the balanced form of a Gysel power divider. The constraint rules are provided for its mixed-mode and single-ended S-parameters. The six-port network is analyzed by simplifying it to two-port networks with other ports matched at the central frequency. Its critical characteristic impedances are then calculated analytically by our derived equations according to the desired differential-mode power division ratio. The maximum achievable power division ratio is 1:4.692 when the characteristic impedances are limited within the realizable range of 20-120 Ω. The impacts of several freely selected design parameters on the operating bandwidth are explored numerically. A prototype is realized by microstrip lines and lumped resistors with the power division ratio of 1:32. The balanced-to-balanced performances of unequal power division, low differential-mode insertion loss, good suppression of common-mode noises, and mode conventions have been demonstrated by the simulated and measured results of the balanced-to-balanced power divider prototype.

Design of a Simple Transition From Microstrip to Ridge Gap Waveguide Suited for MMIC and Antenna Integration

Abstract: This letter describes a simple and low-loss microstrip-to-ridge gap waveguide transition with a very compact geometry. The transition transforms the electromagnetic (EM) fields from the microstrip mode to the air-filled ridge gap waveguide mode. This is achievable if the height of the air gap in the ridge gap waveguide is kept almost equal to the thickness of the substrate of the microstrip line. The transition has a pressure contact between the ridge and the microstrip line, so it works without soldering. This is advantageous in systems that require mechanically separable split-blocks or modules and need a lot of transitions. Experimental results of the manufactured back-to-back transition show an insertion loss of 0.32 dB and a return loss of 14.15 dB over 55% relative bandwidth in Ka-band.

Development of a Low-Profile Circularly Polarized Cavity-Backed Antenna Using HMSIW Technique

Abstract: In this paper, two single fed low-profile cavity-backed planar slot antennas for circular polarization (CP) applications are first introduced by half mode substrate integrated waveguide (HMSIW) technique. One of the structures presents right handed CP (RHCP), while the other one offers left handed CP (LHCP). A single layer of low cost printed circuit board (PCB) is employed for both antennas providing low-cost, lightweight, and also easy integration with planar circuits. An inset microstrip line is used to excite two orthogonal quarter-wave length patch modes with required phase difference for generating CP wave. The new proposed antennas are successfully designed and fabricated. Measured results are in good agreement with those obtained by numerical investigation using HFSS. Results exhibit that both antennas present the advantages of conventional cavity backed antennas including high gain and high front to back ratio (FTBR).

Non-Destructive Thickness Measurement Using Quasi-Static Resonators

Abstract: A microwave sensor for non-destructive measurement of dielectric thickness is presented. The sensor is a quasi-static resonator and based on complementary split ring resonator (CSRR) structure. When the CSRR structure is backed by a conductive medium covered with a dielectric layer the resonance frequency of the CSRR has a strong dependence on the thickness of the dielectric layer. Effect of the size of CSRR sensor on the sensitivity is analyzed numerically. For experimental verification, a CSRR sensor that operates in the 1.6 to 2.3 GHz band is fabricated and excited by a microstrip line.

Frequency Reconfigurable Microstrip Loop Antenna Covering LTE Bands With MIMO Implementation and Wideband Microstrip Slot Antenna all for Portable Wireless DTV Media Player

Abstract: A microstrip slot antenna covering Digital TV (DTV) and frequency reconfigurable microstrip printed loop antenna operating at LTE bands 3 (1.8 GHz) and 7 (2.6 GHz) with multiple-input-multiple-output (MIMO) implementation are designed which can find applications in portable wireless DTV media players. The DTV antenna is matched from 496-862 MHz and LTE bands 3 and 7 from 1710-1880 MHz and 2500-2700 MHz, respectively, all considering S11 = -6 dB matching criterion. Further, the LTE bands antennas are frequency reconfigurable antennas and its MIMO implementation shows an envelope correlation (EC) below 0.22 for both the LTE bands. Prototype antennas were fabricated and experimental verification was performed.

Compact Tri-Band Bandpass Filter Based on $\lambda/4$ Resonators With U-Folded Coupled-Line

Abstract: This letter presents a novel compact microstrip tri-band bandpass filter (BPF) based on $\lambda/4$ resonators. The first and third passbands are realized by coupling the two dual-band $\lambda/4$ stepped impedance resonators (SIRs) with synthesized frequency response. Meanwhile, the second passband in the middle is achieved by introducing the two coupled $\lambda/4$ uniform impedance resonators (UIRs). A non-uniform coupled-line with the U-folded shape on one line is then proposed to independently achieve the dissimilar external couplings as desired in the tri-passbands. In parallel, the quadruplet topology for each band is formulated by introducing an additional weak I/O cross coupling, thereby bringing one pair of transmission zeros at each side of all the triple passbands, In final, a tri-band BPF with the central frequencies of 1.8, 3.5, and 5.8 GHz, and respective fractional bandwidths of 7.0%, 5.0%, and 3.5% is designed and fabricated. The measured results show good consistence with the simulated ones.

A 30-GHz Integrated Subharmonic Mixer Based on a Multichannel Graphene FET

Abstract: A 30-GHz integrated subharmonic mixer based on a single graphene field-effect transistor (G-FET) has been designed, fabricated, and characterized. The mixer is realized in microstrip technology on a 250- μm-high-resistivity silicon substrate. In order to enhance the current on-off ratio, the G-FET utilizes a channel consisting of an array of bow-tie structured graphene, yielding a current on-off ratio of 7. A conversion loss (CL) of 19 ± 1 dB over the frequency range of 24-31 GHz is obtained with a local oscillator (LO) to RF isolation better than 20 dB at an LO power of 10 dBm. The overall minimum CL is 18 dB at 27 GHz. The mixer has a 3 GHz ± 1-dB IF bandwidth, which is achieved with a fixed LO signal of 15 GHz. The mixer linearity is characterized and the highest third-order intercept point is measured to be 12.8 dBm.

Magnetic Near-Field Probes With High-Pass and Notch Filters for Electric Field Suppression

Abstract: Several new types of low-cost and robust magnetic near-field probes manufactured in low-temperature co-fired ceramics (LTCC) are presented in this paper. Parallel C-shaped strips and their variations are inserted into the loop area in the front end of probes to achieve common-mode high-pass and notch filters for electric-field noise suppression. These probes with this kind of filter have excellent wideband electric field suppression. They are called high electric field suppression probes type A ~ D. The size of loop aperture in all probes is 100 μm long and 400 μm wide. The signal received from the loop is routed to a measurement apparatus through a semi-rigid coaxial cable with an outer diameter of 0.047 in. The flip-chip junction with low loss and good shielding is used between the probe head in LTCC and the semi-rigid coaxial cable. We take the probes over a 2000-μm-wide microstrip line as device-under-test to measure the probe characteristics. The isolation between electric and magnetic fields for a reference probe based on an old design using the same LTCC process is better than 30 dB from 0.05 to 12.65 GHz. The type A probe has two parallel C-shaped strips, it has better isolation of 35 dB from 0.1 to 11.05 GHz. Type C has one end of its strip shorted to ground, its 30-dB isolation frequency range can be extended to 0.05 ~ 17.8 GHz. With additional layout variation in type D, isolation can be improved to 40 dB up to 10.9 GHz. The spatial resolution for these probes is 140 μm when the distance between the metal surface of the microstrip line and the nearest edge of the loop is held at 120 μm. The calibration factors of the proposed probes are only slightly increased as compared with reference probe.

Compact and Sharp Skirts Microstrip Dual-Mode Dual-Band Bandpass Filter Using a Single Quadruple-Mode Resonator (QMR)

Abstract: A new type of microstrip dual-mode dual-band bandpass filter (BPF) using a single quadruple-mode resonator (QMR) is proposed in this paper. The classical even-/odd-mode method is applied to analyze the characteristics of the proposed resonator, which shows that it has two pairs of symmetrical resonant modes. Owing to the inherent characteristic of a dual-mode resonator and source-load coupling, four transmission zeros can be produced and these four resonant modes can be divided in two groups, resulting in a dual-band BPF with two resonant modes in each passband. As examples, two dual-mode dual-band BPFs, Filter A with central frequencies (CFs) at 1.99/5.58 GHz and -3-dB fractional bandwidth (FBW) of 62.3%/19.7%, while Filter B with CFs at 1.64/5.26 GHz and -3-dB FBW of 32.9%/7.6%, are designed and fabricated. An aperture-backed compensation technique is employed in such two filters to enhance the coupling strength between the feeding lines and QMR. Furthermore, a meander coupled-line section is employed in the Filter A design, while a defected microstrip structure is introduced in Filter B design, so as to increase much more design freedoms for tuning filter performance. The fabricated two filters exhibit simple design procedures, low insertion losses, good return losses, sharp shirts, and compact sizes. Moreover, two BPFs do not need external input/output impedance transformation feeding lines.

Single-Layer Microstrip High-Directivity Coupled-Line Coupler With Tight Coupling

Abstract: A novel symmetrical coupled-line circuit structure without patterned ground plane is proposed to design tight-coupling high-directivity couplers, which would be found in numerous applications in a microstrip RF front end because of its simple structure and inherent excellent compatibility. Based on a traditional even- and odd-mode technique, closed-form mathematical equations for both circuit electrical parameters and scattering parameters are obtained. Due to the use of two coupled-line sections placed in the vertical direction, the directivity of this novel coupler without any other compensation techniques can be enhanced while maintaining tight-coupling performance of almost 3 dB. For demonstrative purposes, three typical full-wave simulation examples with realized physical dimensions in microstrip technology are presented, indicating high directivity and tight coupling coefficient. Finally, a practical microstrip coupled-line coupler is designed and fabricated to operate at approximately 2 GHz. The measured results show good return loss, quadrature phase characteristics, high directivity, and strong coupling performances.

Effect of the fabrication parameters on the performance of embroidered antennas

Abstract: Simulated and measured microstrip patch antennas produced using embroidery techniques have been presented. The antennas use a standard microwave substrate material. The effect of stitch direction and stitch density is described and a clear requirement to understand how the currents flow in an antenna, so that the stitch direction can be correctly chosen is shown. Two different simulation approaches for these antennas are discussed and one is linked to measurement results, pointing to a simplified model for simulating embroidered patch antennas.

The Use of Metal Filled Via Holes for Improving Isolation in Ltcc RF and Wireless Multichip Packages

Abstract: LTCC MCM's for RF and wireless systems often use metal filled via holes to improve isolation between the stripline and microstrip interconnects. In this paper, results from a 3D-FEM electromagnetic characterization of microstrip and stripline interconnects with metal filled via fences for isolation are presented. It is shown that placement of a via hole fence closer than three times the substrate height to the transmission lines increases radiation and coupling. Radiation loss and reflections are increased when a short via fence is used in areas suspected of having high radiation. Also, via posts should not be separated by more than three times the substrate height for low radiation loss, coupling, and suppression of higher order modes in a package.