Showing papers on "Microstrip published in 1979"

Microstrip Lines and Slotlines

Abstract: Microstrip Lines I: Quasi-Static Analyses, Dispersion Models, and Measurements -Introduction. Quasi-Static Analyses of a Microstrip. Microstrip Dispersion Models. Microstrip Transitions. Microstrip Measurements. Fabrication. Microstrip Lines II: Fullwave Analyses, Design Considerations, and Applications - Methods of Fullwave Analysis. Analysis of an Open Microstrip. Analysis of an Enclosed Microstrip. Design Considerations. Other Types of Microstrip Lines. Microstrip Applications. Microstrip Discontinuities I: Quasi-Static Analysis and Characterization -Introduction. Discontinuity Capacitance Evaluation. Discontinuity Inductance Evaluation. Characterization of Various Discontinuities. Compensated Microstrip Discontinuities. Microstrip Discontinuities II: Fullwave Analysis and Measurements - Planar Waveguide Analysis. Fullwave Analysis of Discontinuities. Discontinuity Measurements. Slotlines -Introduction. Slotline Analysis. Design Considerations. Slotline Discontinuities. Variants of Slotline. Slotline Transitions. Slotline Applications. Defected Ground Structure (DGS) -Introduction. DGS Characteristics. Modeling of DGS. Applications of DGS. Coplanar Lines: Coplanar Waveguide and Coplanar Strips -Introduction. Analysis. Design Considerations. Losses in Coplanar Lines. Effect of Tolerances. Comparison with Microstrip Line and Slotline. Transitions. Discontinuities in Coplanar Lines. Coplanar Line Circuits. Coupled Microstrip Lines -Introduction. General Analysis of Coupled Lines. Characteristics of Coupled Microstrip Lines. Measurements on Coupled Microstrip Lines. Design Considerations for Coupled Microstrip Lines. Slot-Coupled Microstrip Lines. Coupled Multiconductor Microstrip Lines. Discontinuities in Coupled Microstrip Lines. Substrate Integrated Waveguide (SIW) -Introduction. Analysis Techniques of SIW. Design Considerations. Other SIW Configurations. Transitions Between SIW and Planar Transmission Lines. SIW Components and Antennas. Fabrication Technologies and Materials.

Microstrip Tapped-Line Filter Design

Abstract: The subject of this article is a step-by-step design procedure for microstrip tapped-line filters, accompanied by appropriate design curves. In addition to microstrip tapped-line interdigital filters, a new hairpin-line filter using tapping is introduced. The equation to equation the singly loaded Q for hairpin resonators produced by tapping is derived. Experimental data is presented for filters over 20-percent bandwidth.

Analysis of the microstrip disk antenna element

Abstract: The circular microstrip antenna element is formed by a radiating disk closely spaced above a ground plane. It is modeled as a cylindrical cavity with magnetic walls which can be resonant in the transverse magnetic (TM) modes. The far fields and the radiation conductances for different mode structures have been calculated assuming a magnetic line current flowing along the perimeter of the disk. The directivity of a disk antenna excited in the dominant mode is between 4.8 dB and 9.9 dB, depending on the size. Losses, due to imperfect supporting dielectrics and to the finite conductivity of the conductors, have been derived by means of a perturbation technique. Graphs are given for design purposes showing the input impedance, the Q factor, and the radiation efficiency at resonance for different modes and thicknesses. The air-filled microstrip antenna has the highest efficiency and the broadest bandwidth at a given resonant frequency.

Characteristics of Coupled Microstriplines

Abstract: Semiempirical design equations for the even- and odd-mode characteristics of coupled microstriplines are presented. The characteristics include capacitance, effective dielectric constant, impedance, and losses. The coupled line capacitances are obtained by suitably dividing the total capacitance into parallel plate and fringing capacitances. These capacitances are then used to determine other characteristics. The accuracy of characteristic impedances obtained from these capacitances is better than 3 percent. The sensitivity of the characteristics of coupled microstriplines to the tolerance in parameters is described. It is observed that the effect of tolerances on the coupling constant of a directional coupler increases with the increase in the value of coupling constant. The effects of dispersion and the finite thickness of metal strips have been included. It is noticed that the dispersion is more pronounced for even mode, whereas finite strip thickness affects odd mode to larger extent.

Radiation properties of microstrip dipoles

Abstract: The fundamental problem of printed antennas is addressed. The printed or microstrip dipole is considered, and its radiation characteristics are investigated. The Green's function to the problem is obtained in dyadic form by solving the problem of a Hertzian dipole printed on a grounded substrate. Input impedance computations are presented, and the numerical solution for the Sommerfeld integrals is discussed.

Unified user-oriented computation of shielded, covered and open planar microwave and millimeter-wave transmission-line characteristics

Abstract: A unified, rigorous and efficient hybrid-mode solution to the general planar 3-layer transmission-line problem with shielded, covered and open cross-sectional geometry is achieved by the spectral-domain method. Stress is put on the minimisation of the computational expense required to obtain the frequency-dependent design data of planar line structures with realistic geometrical dimensions. This implies the modal propagation constants, uniformly defined characteristic impedances and any field quantities. On the basis of user-oriented considerations a computer program has been developed which is applicable to fundamental, and higher, even and odd modes on single and coupled coplanar strips and slots. This computational approach includes most of the cases which today are of technical interest, e.g. stripline and microstrip, microstrip with dielectric overlay, suspended substrate strips and slots, slotline, coplanar line and grounded or isolated fin line. It combines analytical simplicity, rigorousness and high efficiency with the possibility of performing studies on numerical accuracy and convergence.

Extended analysis of rectangular microstrip resonator antennas

Abstract: An extended theory on rectangular microstrip resonator antennas is presented using the cavity model. Radiation from all four edges of the open cavity is taken into account as well as dielectric and ohmic losses. For a rectangular microstrip antenna excited in its lowest resonance mode, losses, input conductance, and bandwidth are calculated and plotted versus frequency for some different parameters, showing that bandwidths of up to 15 percent (for a voltage standing-wave ratio (VSWR) of less than two) are possible to achieve in the X band.

A new travelling-wave antenna in microstrip

Abstract: The radiation characteristics of the first higher order mode of microstrip lines are investigated. As a result, a simple travelling wave antenna element is scribed, having a larger bandwidth compared with resonator antennas. A method to excite the first higher order mode is shown. A single antenna element is treated theoretically and experimentally, and an array of four antenna elements is demonstrated.

An Approximate Dispersion Formula of Microstrip Lines for Computer-Aided Design of Microwave Integrated Circuits

Abstract: A simple approximate formula for the computer-aided design of the dispersion property of microstrip lines is reported in this paper which well fits the calculated curves based on a rigorous analysis.

Accurate Solution of Microstrip and Coplanar Structures for Dispersion and for Dielectric and Conductor Losses

Abstract: For the analysis of coplanar- and microstrip-type structures, a higher order solution of the spectral-domain approach is introduced. Legendre polynomials are used as the basis functions for fields having singularities near the edges, leading to fast convergence to the exact solution. A perturbation technique is combined with the spectral-domain method to evaluate conductor and dielectric losses in microstrip, inverted microstrip, and coupled microstrip in the metallic enclosure. Computations of characteristic impedance and losses incurred in several structures are also presented. Central processing unit (CPU) time on an IBM 360/65 for the zeroth-order approximation ranges from 1 to about 5 s for the whole computation, and increases if higher order of solution is requested for better accuracy. The calculation of attenuation due to conductor losses is found to be particularly sensitive to order of approximation, so that the generally used "zeroth-order" solution is inadequate. A user-oriented program package has been written, including options on order of mode, order of solution (i.e., of approximation), impedance, attenuation, and number of substrates. Although written for single or coupled microstrip, the program can be adapted for arbitrary arrangements of thin coplanar conductors. The program is described separately.

Wide bandwidth microstrip antennas for circuit integration

Abstract: Novel multilayer concepts for the formation of efficient micro-strip antennas on alumina substrates that allow simple antenna/circuit integration to be achieved are described. Experimental results show that, by using these techniques, bandwidth in excess of 16 times those of alumina microstrip antennas can be obtained, at the expense of an increase in the overall antenna height.

High-frequency behaviour of microstrip open-circuit terminations

Abstract: The extensive use of open-circuit microstrip terminations as tuning stubs and, more recently, as antenna elements, demands design data on the frequency-dependent characteristics of the termination A variational solution for the end admittance is formulated using discrete and continuous mode distributions to represent the radiation, evanescent and substrate surface-wave fields Computed results for a variety of line widths on polyguide and alumina substrates are compared with available experimental and theoretical data It is established that useful admittance curves can be readily calculated using a simple trial aperture field, and the functional form of the curves is independently predicted by a Hilbert-transform relationship The frequency-dependent end admittance reveals the lower frequency range over which a given substrate is suitable for unshielded high-Q circuit applications and the higher-frequency region for microstrip antenna applications The generation of substrate surface waves increases with frequency, and sets an upper frequency limit for microstrip antenna applications Other practical issues of interest such as radiation patterns, intercircuit coupling and resonator losses are briefly considered and the usefulness of this approximate analysis, which represents the most complete treatment to date, is evident

Frequency scanning microstrip antennas

Abstract: The principles of using radiating microstrip resonators as elements in a frequency scanning antenna array are described. The resonators are cascade-coupled. This gives a scan of the main lobe due to the phase-shift in the resonator in addition to that created by the transmission line phase-shift. Experimental results in X -band, in good agreement with the theory, show that it is possible to scan the main lobe an angle of \pm30\deg by a variation of the frequency \pm300 MHz, and where the 3 dB beamwidth is less than 10\deg . The directivity was 14.7 dB, while the gain was 8.1 dB. The efficiency might be improved by a trade-off between the efficiency and the scanning angle, or by using a better amplitude distribution.

Guiding and radiation characteristics of planar waveguides

Abstract: Planar waveguides like microstrip and microslot have been used not only as waveguides but also for radiation purposes (microstrip antennas). Therefore, this paper tries to give a clear description of waveguide characteristics as well as radiation characteristics of planar waveguides. The differences between the several modes, i.e. the guided modes, the radiation modes and the leaky waves, are clarified. Moreover, computed results as well as experimental results of different mode characteristics are presented.

Curved microstrip lines as compact wideband circularly polarised antennas

Abstract: A new technique for the inherent generation of circular polarisation from compact microstrip antennas is described, based on radiation from curved microstrip transmission lines supporting a single travelling wave. The radiation is analysed in terms of effective magnetic current sources to give an estimate of the decay coefficient of the wave, which is found to be in reasonable agreement with experiment. Good characteristics are obtained from both circular and spiral antennas, with a useable bandwidth of up to 40% being available at 10 GHz for an average efficiency of 50%, owing to power absorbed in the line termination. The advantages obtained over conventional microstrip circular-polarised antennas are the avoidance of band-width limitations owing to resonant matching and the elimination of feed networks to produce circular polarisation.

Various Excitation of Coplanar Waveguide

Abstract: This paper reviews various methods to excitate propagation along coplanar waveguide (C.P.W); some very useful transitions are completly described and the performances obtained on transitions such as coplanar to coax, coplanar to microstrip or coplanar to slot line are given. Examples of application in microwave integrated circuits illustrate the employment of these transitions.

Average power-handling capability of microstrip lines

Abstract: An expression for the average power-handling capability (a.p.h.c.) of microstrip lines is derived by considering the heat generated in the strip conductor and the dielectric substrate. The analogy between electrostatic fields and heat-flow fields is used for calculation of the rise in temperature of the strip conductor. The computed value of a.p.h.c. for a 50 Ω line on alumina substrate (0.06 cm [25 mil] thick) is 5.26 kW at 10 GHz whereas the corresponding figure for polystyrene substrate is 126 W.

Low noise microstrip voltage controlled oscillator

Abstract: The invention comprises a microwave oscillator using a stripline circuit. The active device utilized in the oscillator is a bipolar transistor. A microstrip circuit is coupled to the emitter of the transistor while the collector is coupled to ground. This generates a negative impedance characteristic at the base of the transistor at the operating frequency. The operating frequency is determined by a varactor which is series tuned with an inductor. The impedance of the series tuned circuit is transformed to match the input impedance of the transistor by a microstrip circuit. Microstrip isolation circuits are utilized to couple appropriate bias signals to the emitter and the base to establish the proper operating point for the bipolar transistor. The output signal is taken from the base circuit of the transistor through the series combination of two microstrip circuits and a capacitor. A second varactor is loosely coupled to the base circuit of the transistor to provide for fine tuning. The frequency control characteristic of the oscillator can be made linear by utilizing a hyper abrupt varactor.

An Appraisal of Methods for Computation of the Dispersion Characteristics of Open Microstrip

Abstract: A number of methods in the literature for computing the dispersion characteristics of open microstrip are compared in the case when substrate thickness is comparable to strip width. Significant discrepancies between the various results are found, and several suggestions are made to explain them.

Improved theory for microstrip antennas

Abstract: An improvement to a recently reported theory for the analysis of the pattern and impedance loci of microstrip antennas is developed. It yields a theory that is simple and inexpensive to apply. This is achieved by lumping all antenna losses into an effective dielectric loss tangent and then analysing the microstrip antenna as a lossy cavity. It is found that the resulting expression for impedance of the microstrip antenna is in good agreement with measured results for all modes and feed locations.

Microwave directional coupler and detector module

Abstract: A module board comprised of a microstrip transmission line, terminating resistors and detectors is mounted over two coupling apertures spaced one quarter guide wavelength along a rectangular waveguide. The microstrip line has a length of five quarters of a wavelength as measured in the secondary line system. Output signals representing forward and reflected power flow in the waveguide are developed by the two detectors. This power sensor is low cost and compact and is suitable for a microwave oven.

Microstrip antenna technology at ball aerospace systems, Boulder, Colorado

Abstract: The reviewer should also make notes on the manuscript wherever English usage and/or grammar are incor rec t o r poor. Remember the IEEE E d i t o r i a l Department usual ly does an excellent job correcting author manuscripts; so the reviewer should not feel obl iged to cor rec t every detai l of Engl ish, e tc . This is a lso t rue wi th regard t o format and standardization of mathematical expressions. The reviewer must make eve ry e f fo r t t o complete the review within the al located four-week per iod; in fac t , i f the rev iewer cannot meet t h i s commitment, he should inform the Editor or Associate Edi tor , who s e n t him the manuscript , when he receives it. Al of these points are indicated or implied by the current review forms; however, it is seldom t h a t a reviewer takes the time t o w r i t e a t l e a s t one sentence on a l l o f t he above items.

Design equations for coupled microstrip lines

Abstract: Closed form capacitance expressions for the even and odd mode characteristics of coupled microstrip lines are presented. These expressions are accurate to within 3% for 0.2≤W/h≤2, 0.05≤S/h≤2 and ϵrl. Extension of these results to asvmmetriu coupled microstrip lines indicate an accuracy of about 5% for ϵ = 10, W/h = 0.95, W2/h≥0.2and S/h≥0.1

Spectral Domain Immittance Approach for Dispersion Characteristics of Shielded Microstrips with Tuning Septums

Abstract: A method for deriving dispersion relations in a new versatile MIC transmission line, a microstrip line with tuning septums, is developed based on the spectral domain immittance matrix. Formulation is accomplished almost by inspection. Some examples of numerical results are included.

A Fast Low-Loss Microstrip p-i-n Phase Shifter

Abstract: A 4-bit p-i-n phase shifter with low RF attentuation, fast switching time, and low switching power requirements is described. The circuit, made in microstripline, consists of four cells giving phase shifts of 180, 90, 45, and 22.5/sup deg/, respectively. Each cell consists of a 3-dB coupler loaded by two p-i-n diodes. The transmission loss is 1.6 dB /spl plusmn/ 0.2 dB over the operating bandwidth of 11.7-12.2 GHz for a biasing current of only 5 mA/cell. Switching time between phase states is 1 ns.

The Reflection Definition of the Characteristic Impedance of Microstrips

Abstract: The frequency-dependent characteristic impedance shielded microstrips is computed by the scattering matrix of the step of rectangular transmission line to the shielded microstrip including higher order hybrid modes. This method avoids the ambiguities of the hitherto known definitions based on TEM quantities. For the dispersion characteristics a resonant model is used which reduces the number of the characteristic equations required. Numerical results are given including strips of finite thickness placed unsymmetrically in the shielded microstrip.

Radiation from Microstrip Discontinuities

Abstract: Radically different methods of calculation by Lewin and by van der Pauw are compared. It is shown that the difference in the two sets of results is due not to the difference in method, but to assumptions on the value of dielectric constant to be used when calculating the substrate polarization. Curves show that differences of up to 30 percent can arise from this source, but the differences are much smaller for the larger values of dielectric constant.

On the Use of a Microstrip Three-Line System as a Six-Port Reflectometer

Abstract: The scattering parameters for a coupled symmetrical three-Iine system in an inhomogeneous dielectric medium (e.g., microstrip) are derived directly in terms of a set of three orthogonal modes. The obtained results show that the condition for isolation of nonadjacent ports (e.g., ports 1 and 3 in Fig. 1) does not result from putting the corresponding per unit length immittance parameters equal to zero (i.e., z/sub 13/ =y/sub 13/ = 0). The use of such a three-line system as a six-port reflectometer is analyzed in terms of the derived scattering parameters. The reflectometer discussed in this paper allows an unknown impedance to be measured using a standard impedance.

Modified circular microstrip antenna elements

Abstract: The addition of radial conducting strips to microstrip disc antenna elements alters the circuit and radiation behaviour. Frequency shift, pattern modification and dual-frequency operation can be obtained by proper selection of the strip parameters.

Calculation of the Bandwidth of Microstrip Resonator Antennas

Abstract: In this paper one presents an analysis of the bandwidth of microstrip resonator antennas in function of the antenna parameters. Starting from the general expression for the quality factor of a resonator, it will be proved that the bandwidth of a microstrip resonator antenna is directly proportional to the thickness of the substrate, to the square of the resonant frequency and inversely proportional to the square root of the relative permittivity of the substrate material. Comparing the theoretical results with experimental data one finds a good agreement.