Phase Difierence Research Articles

A SIMPLE 2×3 BEAM-FORMING NETWORK WITH A 2-BIT PHASE SHIFTER FOR FOUR-BEAM RECONFIGURATION

A simple 2£3 reconflgurable beam-forming network (R-BFN) for four-beam reconflguration application is designed and implemented. The proposed R-BFN with two input ports and three output ports consists of a 2:1 power divider, a 90 - hybrid, a 180 - hybrid and a 2-bit phase shifter. The 2- bit phase shifter has two states: one is a 180 - phase shifter (State 1); the other is a 0 - =360 - phase shifter (State 2). By introducing the 2-bit phase shifter, the constant phase difierences of three output ports can be reconflgured. When the proposed R-BFN is connected to an antenna array, a four-beam reconflguration is obtained. Simulated and measured results show that good impedance matching, high port isolation, equal power division, and constant phase difierence have been achieved simultaneously within the operation band of 2.4{2.6GHz. The capability of the proposed R-BFN to reconflgure beams is also verifled experimentally by using a 2.5GHz dipole array.

SURFACE PLASMON RESONANCE PHASE-SENSITIVE IMAGING (SPR-PI) SENSOR BASED ON A NOVEL PRISM PHASE MODULATOR

A novel prism phase modulator (PPM) for phase difierence modulation between p- and s-polarization lights in a surface plasmon resonance phase-sensitive imaging sensor is proposed in this paper. The PPM consists of a rhombic prism (to obtain a curve of phase difierence between the two polarizations), a rotation stage and a mirror. The PPM shows great modulation stability and helps to achieve a high detection resolution. Surface plasmon resonance phase imaging is realized with a micro∞uidic device and a CCD camera. Experimental result shows that the detection resolution of our SPR-PI sensor based on phase-interrogation method is 7:61 £ 10 i7 RIU with hydrous samples, which is 16 times improved compared with that based on intensity-interrogation. Real-time monitoring of the interaction between Angiogenin and anti-Angiogenin is also illustrated.

REAL TIME IMPLEMENATION FOR DOA ESTIMATION METHODS ON NI-PXI PLATFORM

In this paper, we present flve difierent approaches to estimate direction of arrival (DOA) of multiple incident RF sources. The proposed methods are based on extracting the signal and noise subspaces from the Q matrix, R matrix, or both Q and R matrices of the QR decomposed received data matrix. The angle of the signal arrival is extracted from the signal subspace by using similar techniques as employed by MUSIC and ESPRIT methods. The simulation results are shown which verify accurate DOA estimates for both single and two sources. In addition, an experimental veriflcation of the proposed methods is also presented. The methods are implemented in LabVIEW software and a prototype is built using National Instruments (NI) hardware. Furthermore, the details of experimental procedures are presented which includes interfacing the uniform linear array (ULA) of antennas with the NI-PXI platform, phase difierence calibration between the RF receivers, and selection of transmitter and receiver parameters. The experimental results are shown for a single and two RF sources lying at arbitrary angles from the array reference, which verify the successful real-time implement-ability of the proposed DOA estimation methods.

SIMULATION AND IMPLEMENTATION OF A NEW X-BAND 1:4 POWER DIVIDER/COMBINER BASED ON A NEW WAVEGUIDE <I>H</I>-PLANE FOLDED MAGIC-T

This paper presents the simulation and fabrication of a new power divider/combiner based on a new waveguide H-plane folded magic-T structure. Measurements of the fabricated magic-T conflrm the accuracy of the optimization algorithms existing in the CST software (Genetic algorithm, Particle Swarm Optimization algorithm PSO etc.). The magic-T structure exhibits moderate bandwidth response in the frequency range of 8{10GHz. Also, it shows that the return loss is better than i15dB, the insertion loss about i3:4dB, and the isolation between the two output ports better than i25dB in the frequency range of 8.4{10GHz, with good transmission phase characteristics. Based on this magic-T structure, a 1 : 4 power divider/combiner is simulated and tested. The measured results show that the insertion loss is about i6:5§0:25dB, the return loss less than i15dB, the isolation among the output ports less than i25dB, the combining e-ciency about 89%, and the transmission phase difierences are about §2 - in the frequency range of 8{10GHz.

LOSS REDUCTION IN SUBSTRATE INTEGRATED WAVEGUIDE STRUCTURES

A method for decreasing the loss in substrate integrated waveguide (SIW) structures is introduced. In this method, the dielectric substrate is partially removed. Accordingly, dielectric loss reduction has been explicated analytically. Its equivalence to the rectangular waveguide of solid walls which is partially fllled with dielectric has been identifled. A novel topology for demonstrating the idea is established and a low loss three port substrate integrated waveguide power divider is presented. This SIW power divider shows lower loss than conventional SIW power dividers. Proper TRL standards are realized for removing the efiect of transition and/or matching sections in measurement process. For a low-loss three-port PSIW power divider, the return loss below 10dB and transmission coe-cients between i3dB to i3:5dB from 8.75GHz to 10GHz have been achieved. The measured amplitude imbalance is less than §0:2dB, and the measured phase difierence between \S21 and \S31 is about 4 - in the same frequency band.

DESIGN OF A WIDEBAND DIFFERENTIAL PHASE SHIFTER WITH THE APPLICATION OF GENETIC ALGORITHM

In this paper, a wideband difierential phase shifter has been analyzed and designed using Genetic Algorithm (GA). The difierential phase shifter consists of two flxed main lines of length ‚/2, and parallel open and short stubs of length ‚/8, which are shunted at the edge points of the main lines, respectively. With the application of GA, an impedance match and minimum phase deviation for the desired phase shift over a wide frequency band are obtained. In order to verify the optimum results, simulation experiments are made and a 45 - phase shifter is fabricated and measured. The phase shifter exhibits an impedance bandwidth (jS11j < i10dB) and a consistent 45 - (§2 - ) phase difierence bandwidth around 66%.

ANALYSIS OF TEMPORAL POLARIZATION PHASE DIFFERENCE FOR MAJOR CROPS IN INDIA

A polarimetric radar system measures the complete scattering matrix of a target in the backscattered fleld that includes magnitudes of linearly polarized scattering amplitudes and the co- polarised and cross-polarised phase angles. Apart from backscattering intensity, the co-polarization phase difierence (CPD) calculated from polarimetric synthetic aperture radar (SAR) data produces important information about target physical, geometrical and dielectric properties. In the present work, the distribution of CPD in C-band polarimetric SAR data corresponding to major kharif and rabi crops (denoting the monsoon and the winter season) and other land cover features have been studied over Central State Farm, Hisar, Haryana. The probability density functions (PDF) of CPD have been compared with dominant scattering contributions from these targets as obtained from polarimetric target decompositions. The results show that crops and other land cover features show characteristic CPD distributions, which relates well with crop physical and geometrical properties. An intuition of the rate of growth and plant vigour is indicative from the temporal PDF pattern.

A NOVEL MULTI-WAY POWER DIVIDER DESIGN WITH ARBITRARY COMPLEX TERMINATED IMPEDANCES

A simple and analytical design methodology for a novel multi-way Bagley Polygon power divider with arbitrary complex terminated impedances is proposed in this paper. The design parameters including electrical lengths and characteristic impedances can be obtained by the provided closed-form mathematical expressions when complex terminated impedances are known. Moreover, for convenient test, we design an impedance transformer to transform the complex impedance into real impedance using an extension line, and especially a re∞ection coe-cient chart to solve it. Four special cases of 3-way Bagley Polygon power divider operating at 2.4GHz are fabricated and measured with difierent condition complex terminated impedances for the purpose of veriflcation. Excellent agreement between simulation and measurement results proves the validity of the design method. The presented Bagley Polygon power divider exhibits 180 - phase difierence between any two adjacent output ports and 0 - phase difierence between two symmetrical output ports and is suitable for multi-antenna and difierential antenna system. Furthermore, simple layouts lead to convenient design procedure and easy fabrication.

DESIGN OF DUAL-FEED DUAL-POLARIZED MICROSTRIP ANTENNA WITH HIGH ISOLATION AND LOW CROSS POLARIZATION

A broadband dual-feed dual-polarized microstrip antenna with low cross polarization and high isolation is presented. The dual- orthogonal linearly polarized mode is excited by two difierent feed mechanisms from a single circular radiating patch. One of the two modes is excited by a pair of L-shaped probes with a 180 - phase difierences, and the other is excited by an H-shaped aperture. The proposed design has a very simple antenna structure with a wide input impedance bandwidth (23.25% for Port 1 and 35% for Port 2) and also its two input port isolation is found to be as low as i40dB. Measured results of the fabricated antenna prototypes are also carried out to verify the simulation analysis.

A BROADBAND CIRCULARLY POLARIZED ANTENNA FED BY HORIZONTAL L-SHAPED STRIP

A new design of broadband circularly polarized antenna is proposed. The antenna is composed of a square patch and a horizontal L-shaped stripline that feeds the patch at two orthogonal directions by two probes. The L-shaped feeding structure provides excitements of approximately equal amplitude and 90 - phase difierence and then good circularly polarized characteristics are obtained. Measured results show that the proposed antenna has 10-dB impedance bandwidth of 14.3% (2.27{2.62GHz) and 3-dB axial-ratio bandwidth of 13.1% (2.3{ 2.62GHz). Moreover, the measured gain is over 7dBic within the efiective band.

DESIGN OF SEVERAL POWER DIVIDERS USING CPW-TO-MICROSTRIP TRANSITION

Based on the theory of microstrip-to-slotline transition, a series of power dividers with CPW-to-microstrip transition is developed. These power dividers can be made to be coplanar or non- coplanar structure, and the phase difierence between the two output ports can be ∞exibly achieved in phase or out of phase. Two microstrip feed lines couple the energy from the two slots of the CPW with equal magnitude, thus realizing CPW-to-microstrip transition. An in-phase power divider and an out-of-phase one are designed, fabricated and measured. The measured results show that the power dividers provide good return loss, low insertion loss, and stable phase between the two output ports over the operating frequency band.

THEORY OF ZERO-POWER RFID SENSORS BASED ON HARMONIC GENERATION AND ORTHOGONALLY POLARIZED ANTENNAS

In this paper a novel approach is proposed to solve the issue of the absolute accuracy required by the most of the passive chip-less RFID sensors. To this purpose the sensor information is encoded as the phase difierence between two signals, one of the two acting as the reference signal for the other one. First the tag receives a carrier at frequency f0, then two equal signals at frequency 2f0 are generated by means of a diode-based frequency doubler and a power divider. At this point one of the two signals is phase-shifted using a passive sensing element. Finally the 2f0 signals are re-irradiated by exploiting two orthogonally polarized antennas. With this approach the sensor information can be extracted by a suitable reader equipped with two complex (I/Q) receivers. The idea will be flrst developed from a theoretical basis and then verifled with several particular cases. The novel tag concept is compatible with paper substrate and inkjet printing technology since antennas diodes and passive sensing elements, i.e., all the main tag components, are going to be developed on paper materials.

UNIQUE-PLANAR VIALESS MARCHAND BALUN WITH NOVEL METHOD OF MEASUREMENT

A unique-planar vialess Marchand balun for V-band application is presented. The balun can achieve less than 2 - phase imbalance and 0.3dB amplitude imbalance from 54GHz to 66GHz, with the insertion losses of i3:6dB and i3:9dB for the two balanced ports and the return loss of less than i15dB in the unbalanced port. The novel back-to-back measured method has been proposed and analyzed, the amplitude and phase imbalances can be derived from the measured back-to-back two-port scattering results. The extracted results achieve good agreement with the single balun simulation, with no more than 0.15dB and 1 - amplitude and phase difierences. This balun conflguration and the measurement method can simplify the fabrication, achieve good yield, ease the assembling and decrease the cost.

GENERALIZED IMPEDANCE-TRANSFORMING DUAL-BAND BRANCH-LINE COUPLERS FOR ARBITRARY COUPLING LEVELS

High-performance dual-band Doherty power amplifler and non-uniform circularly polarized antenna array require impedance- transforming unequal dual-band 90 - branch-line couplers for power dividing and phase shifting in the feed networks. In this paper, an analytical design methodology of generalized impedance-transforming dual-band branch-line couplers for arbitrary coupling levels is proposed. The coupler features wide range of realizable frequency ratio, multiple ∞exible selections of open- or short-circuited and pi- or T-network topologies. For demonstration, four numerical examples with difierent parameters are presented. Furthermore, two microstrip couplers based on open-circuited pi- and T-network topologies were fabricated and measured. The measured results show good performance at dual 1.8/3.45GHz bands. The fractional bandwidths deflned by the ∞uctuation of the coupling level and the phase difierence less than §0:5dB and §5 - are up to 17% and 18%, 18% and 2% for open-circuited pi- and T-network topologies, respectively.

DEVELOPMENT OF A NEW APPROACH FOR HIGH-QUALITY QUADRUPLING FREQUENCY OPTICAL MILLIMETER-WAVE SIGNAL GENERATION WITHOUT OPTICAL FILTER

In this paper, we propose a new approach to generate quadrupling-frequency optical millimeter-wave (mm-wave) signal with carrier suppression by using two parallel Mach-Zehnder modulators (MZMs) in Radio-over-flber (RoF) system. Among the numerous properties of this approach, the most important is that a fllterless optical mm-wave at 60GHz with an optical sideband suppression ratio (OSSR) as high as 40dB can be obtained when the extinction ratio of the MZM is 25dB. Simplicity and cost-efiectiveness have made this approach a compelling candidate for future wave-division-multiplexing RoF systems. Theoretical analysis is conducted to suppress the undesired optical sidebands for the high-quality generation of frequency quadrupling mm-wave signal. The simulation results show that a 60GHz mm-wave is generated from a 15GHz radio frequency (RF) oscillator with an OSSR as high as 40dB and an radio frequency spurious suppression ratio (RFSSR) exceeding 35dB without any optical or electrical fllter when the extinction ratio of the MZM is 25dB. Furthermore, the efiect of the non-ideal RF-driven voltage as well as the phase difierence of RF-driven signals applied to the two MZMs on OSSR and RFSSR is discussed and analyzed. Finally, we

REALIZATION OF MINIATURIZED QUADRATURE HYBRID COUPLER WITH REDUCED LENGTH BRANCH ARMS USING RECURSIVELY LOADED STUBS

This paper presents a novel design of miniaturized microstrip quadrature coupler at 2.45GHz. The design topology is based on reduced transmission line branch arms using recursively loaded stubs that contribute to the compact size. The proposed coupler result in a size reduction of 70.4% when compared to a conventional branch line hybrid. The designed coupler provides, at the operating frequency, a 25dB isolation and exhibits equal power division at the output ports with quadrature phase difierence. A fabricated prototype is developed with simulation and measurement in close agreement.

A MINIATURIZED TRIPLE-BAND BRANCH-LINE COUPLER BASED ON SIMPLIFIED DUAL-COMPOSITE RIGHT/LEFT-HANDED TRANSMISSION LINE

A miniaturized triple-band branch-line coupler based on the simplifled dual-composite right/left-handed transmission line (S-D-CRLH-TL) is proposed in this paper. The electromagnetic characteristics of S-D-CRLH-TL are analyzed by the simulator and equivalent circuit model, and the results prove that there are three frequency points with phase of i90-degree in the passbands; this characteristic can be used to design triple-band quadrature microwave components. The proposed branch-line coupler is fabricated and measured, the measured and simulated results are in good agreement with each other, showing that the triple-band operating at 3.06GHz, 4.00GHz and 5.54GHz, the useful bandwidths are 2.97GHz{3.16GHz, 3.82GHz{4.12GHz and 5.48GHz{5.67GHz. In addition, compared with the conventional branch-line coupler, the whole size of the proposed one is 17mm£14:4mm (0:173‚£0:147‚) (‚ is the wavelength in low frequency), it realizes a 73% size reduction. Moreover, compared with the triple-band branch-line coupler based on the double-Lorentz transmission line metamaterial, the proposed branch-line coupler is more efiective in the situation, which is sensitive to phase-changing, as the sign of phase difierence in the two outputs at the three frequency points keeps the same.

GENERALIZED ANALYTICAL DESIGN OF BROADBAND PLANAR BALUNS BASED ON WIRE-BONDED MULTICONDUCTOR TRANSMISSION LINES

A novel generalized design procedure of broadband planar baluns based on wire-bonded multiconductor transmission lines (MTL) is presented hereby based on analytical equations. The proposed balun consists of two parts. The flrst one is an in-phase power divider, which equally splits the input power through its two outputs. The later are two MTLs with wire bonding between alternate conductors conflgured to introduce +90 and i90 degrees phase shift respectively, so that the balanced output signal has a 180 degree phase difierence. In that sense, new closed-form design equations in order to calculate the design parameters of both multiconductor elements are obtained. These equations allow the proper dimensions of both MTLs to be computed irrespective of both the number of conductors and the coupling factor, and therefore, to determine the performance of the balun. The design procedure for wire-bonded MTL baluns has been assessed by means of full-wave electromagnetic simulations and by experimental work. In addition, the very good agreement between the theoretical results and measurements makes possible to deflne a time-saving design methodology.

INVESTIGATION OF DUAL-BAND BALUN BANDPASS FILTERS BASED ON COUPLED RING RESONATORS

An investigation of dual-band balanced-to-unbalanced (blaun) bandpass fllters (BPFs) is presented in this letter. Two types of balun BPFs named Type-A and Type-B fllters based on coupled ring resonators are discussed and fabricated. Both the simulated and measured results show that these balun-BPFs have not only good amplitude performances but also excellent phase difierence performances. The center frequencies of these balun BPFs are set at 2.4GHz/5.6GHz for Type-A and 1.57/4.65GHz for Type-B balun fllters. The difierences are 180 - §5 - in phase and within 0.6dB in magnitude of type A and 0.73dB of type B, respectively. Thus, these balun BPFs can be used in many wireless communication systems.

HARDWARE IMPLEMENTATION OF A PROPOSED QR-TLS DOA ESTIMATION METHOD AND MUSIC, ESPRIT ALGORITHMS ON NI-PXI PLATFORM

In this paper, we present an experimental veriflcation of a novel QR-TLS algorithm. Two other algorithms for direction of arrival (DOA) estimation of multiple incident source signals called multiple signal classiflcation (MUSIC) and estimation of signal parameters via rotational invariance techniques (ESPRIT) are implemented on a National Instruments (NI) PXI platform. The proposed method is based on subspace decomposition of a received data into a signal and a noise space using QR decomposition. The angle of the signal arrival information is extracted from the signal subspace by using the method of total least squares (TLS). The algorithms are implemented in LabView NI hardware. The experimental procedures are discussed in details which includes interfacing of the uniform linear array (ULA) of antennas with the NI-PXI platform, calibrating phase difierences between the RF receivers, and selecting transmitter and receiver parameters, for determining the DOAs of the multiple incident source signals. The experimental results are shown for a single and two sources lying at arbitrary angles from the array reference to verify the successful real time implementation of the proposed and other DOA estimation algorithms.