This paper presents a compact 0.92/2.45-GHz dual-band directional circularly polarized (CP) microstrip antenna for handheld radio-frequency identification (RFID) reader applications. The proposed comprises wideband dual-feed network and two stacked concentric patches assembled by orthogonally placed vertical probes. feeds quadrature signals across the RFID bands between 0.92 2.45 GHz. provide resonance frequencies in fundamental mode lower band higher band, respectively. Additionally,...

A dual-band 0.92/2.45 GHz circularly-polarized (CP) unidirectional antenna using the wideband dual-feed network, two orthogonally positioned asymmetric H-shape slots, and stacked concentric annular-ring patches is proposed for RF identification (RFID) applications. The measurement result shows that achieves impedance bandwidths of 15.4% 41.9%, 3-dB axial-ratio (AR) 4.3% 21.5%, peak gains 7.2 dBic 8.2 at 0.92 2.45 bands, respectively. Moreover, provides stable symmetrical radiation patterns...

In this paper, a planar miniaturized arbitrary phase-difference coupler with coupling coefficients is proposed. The proposed consists of three coupled-line sections which achieves compact circuit layout in microstrip implementation. parameters novel can be easily determined by the derived closed-form equations and corresponding performance analysis terms bandwidth miniaturization requirement provided. Two prototypes structure, operating at 2 GHz, have been designed implemented using...

This letter proposes a novel design approach of wideband 90 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> phase shifter, which comprises stepped impedance open stub (SIOS) and coupled-line with weak coupling. The result analyses demonstrates that the bandwidths return loss (RL) deviation (PD) can be expanded by increasing ratio SIOS coupling strength coupled-line. For RL > 10 dB, insertion (IL) 1.1 PD ±5 , fabricated microstrip...

Additive manufacturing technology has enabled the of complex structures, especially those with intricate internal features. This paper proposes a method for building complex-structured millimeter-wave waveguides using strategy that combines digital light processing 3-D printing technology, curved corner design, an off-axis print angle 45°, and robust postmetallization process. To demonstrate capability this combined-strategy method, traditional magic tee prototype adapted inherently matched...

A compact wideband circularly polarized (CP) patch antenna utilizing a quad-feed network (QFN) and quadruple semi-fan-annulus (QSFA) patches is proposed. For using coupled-line dual-band power divider (PD) improved phase shifter (PS) with stepped-impedance-open-stub (SIOS), the QFN has size exhibits electromagnetic (EM) simulated bandwidth over 96% for distribution -6.5±0.5 dB, return loss (RL) > 14 consistent 90° (±9°) deviation. Moreover, QSFA can expand CP reduce of effectively....

A low-cost compact circularly polarized (CP) directional antenna is proposed for universal ultra-high frequency (UHF) RF identification (RFID) handheld reader applications. The consists of four sequentially rotated inverted-F antennas (IFAs) fed by a four-feed network with closed-form design formulas. prototype implemented FR-4 substrates and thick air layer the reduction cost. For return loss (RL) > 13 dB, 3-dB gain variation, axial ratio (AR) , achieves measured bandwidth 14.9% exhibits...

Using a modified version of the Tollens' Test, acrylate-based polymer prints made using consumer-grade Digital Light Projection Stereolithographic (DLP-SLA) 3D printer are successfully silver plated, without need for complex surface preparation techniques. A single-piece prototype waveguide design is used testing plating process, and discussion provided on minimizing printing process variables such as polymerization shrinkage undesirable geometric tolerance variance. Measurement results...

A novel hybrid coupler with nonstandard phase difference has been reported recently by Wong <etal xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"/> in 2012, which shows promising potentials applications like the feeding networks for phased array antenna. However, it is found that design equations of are incomplete because neglect an interrelated constrain between parameters ( <formula formulatype="inline" xmlns:xlink="http://www.w3.org/1999/xlink">...

A turnstile junction orthomode transducer (OMT) provides polarization separation/combining on a full waveguide bandwidth; however, it bears complex connecting structure, which accordingly leads to bulky volume. We present compact W-band (75-110 GHz) OMT using "swan neck" twist for the connection between and an E-plane Y-junction, minimizing overall structure. The core volume proposed is 9× less than previously reported stacked-layer OMT. was built by digital light processing (DLP) 3-D...

A generalized two-way coupled-line power divider with extended ports for dual band is proposed in this paper.The composed of two section coupled-lines, one conventional transmission line, and an isolation resistor, employs extension a line or at each port.The design equations are obtained based on even-and odd-mode analysis, analytical ideal closed-form scattering parameter expressions derived.Because the traditional ring structure special case coupled four cases discussed compared.In...

Traditional hollow metallic waveguide manufacturing techniques are readily capable of producing components with high-precision geometric tolerances, yet generally lack the ability to customize individual parts on demand or deliver finished low lead times. This paper proposes a Rapid-Prototyping (RP) method for relatively low-loss millimeter-wave waveguides produced using consumer-grade stere-olithographic (SLA) Additive Manufacturing (AM) technology, in conjunction an electroless...

This paper introduces an innovative method to fabricate a coaxial transmission line using low-loss 3D printed dielectric and liquid metal conductor. The part is from low loss factor resin, cyanate ester (tanδ = 0.0046). inner conductor formed by pumping eutectic gallium indium (EGaIn) through the empty channel of part, outer electrolessly plated with silver then coated EGaIn. An implemented 2-inch straight shows measured insertion 0.26 dB/cm at 10 GHz, which 1/3 that common printing...

A novel hybrid coupler aiming for wide-band applications is proposed in this paper. This consists of a broadband Wilkinson coupled-line power divider and an improved phase shifter. Taking advantage the section, achieves both compact circuit configuration performance. In lieu patterned ground plane lumped capacitors, shifter can be constructed on single-layer printed board operation. For shifter, scattering parameters (S-parameters) expressions are derived optimal structural design achieving...

The high-directivity single- and dual-band directional couplers based on substrate integrated coaxial line (SICL) are first proposed in this paper. As the SICL features propagation of TEM mode, coupler can keep its compared with microstrip one. also characterizes a vias-shielded structure keeping it away from lateral leakage, cross-talk or unwanted parallel-plate mode. design approaches proper width-spacing given. Experiments carried 2.35 GHz 0.8/2.35 coupler. Compared couplers, ones show...

In this paper, a novel substrate integrated waveguide (SIW) to coaxial line (SICL) transition using the 3dB SIW power divider (PD) and 180 - phase shifter (PS) is proposed. The SIW-to-SICL realizes easy integration of SIW, SICL, active device in same microwave communication system based on substrate-integrated technology (SIT). To validate design concept, prototype has been fabricated measured. Measurements are good agreement with simulations, shows that features ultra-low insertion loss...

A planar, simplified, dual-band rat-race hybrid with arbitrary power division ratio is presented. It accomplished by inserting only single additional shunt stub in the conventional structure and modifying lengths characteristic impedances of arms. Using rigorous even- odd-mode analysis, explicit closed-form equations for this are derived. Based on standard microstrip technology, relationship between realizable power-split ratios frequency investigated. As a generalized design, it found that...

A simple and analytical design methodology for a novel planar four-port structure to implement power divider (PD) or balun with variable division is proposed in this paper. It consists of two difierent 3dB branch-line couplers one coupled-line phase shifter whose length can be changed division. Difierent from the previous designs, realized only circuit by changing electrical µ0 coupled line when impedance ratio g selected. According ABCD parameters linear algebra calculation, closed-form...

Abstract A novel arbitrary asymmetric branch-line coupler structure terminated by one group of complex impedances is proposed. Two left ports the proposed are equal impedances, and other two right real impedances. Arbitrary power division ratios feasible for structure. Using rigorous even- odd-mode analysis scattering parameters theory based on closed-form design formulas designing obtained. To validate given equations, a microstrip operating at center frequency 2.5GHz 20 30 − 6j Ohm...

High-performance dual-band Doherty power amplifler and non-uniform circularly polarized antenna array require impedance- transforming unequal 90 - branch-line couplers for dividing phase shifting in the feed networks. In this paper, an analytical design methodology of generalized impedance-transforming arbitrary coupling levels is proposed. The coupler features wide range realizable frequency ratio, multiple ∞exible selections open- or short-circuited pi- T-network topologies. For...

Abstract The purpose of this article is to propose a novel design method for miniaturized tri-band Wilkinson power dividers with independently controllable center frequencies and simple structure. Different from the traditional circuit using three-section transmission-line transformers, proposed structure consists coupled lines three isolation resistors. Due flexible even- odd-mode parameters inherent small size features parallel lines, compact divider not only provides arbitrary operation...

We report on a complete fabrication process to realize complex, high-performance microwave components using digital-light-processing (DLP) 3D printing. Our approach addresses numerous challenges of successful component realization, including: metalization acrylate-based polymers, defect reduction in printing, increased precision through off-axis printing waveguide channels and re-design internal structures for self-supporting the build process. The results our have produced complex with...

In this paper we study the problem of converting a tracking controller to manoeuvre regulation for nonlinear nonminimum phase control system. First, controller, consisting feedforward and static state feedback, is designed guarantee uniform asymptotic trajectory tracking. The determined by solving stable noncausal inversion problem. Constant feedback gains are based on LQR optimization assumed satisfaction robustness inequality. A obtained from introducing suitable projection that related...