Showing papers on "Microstrip antenna published in 1977"

Resonant frequency of a circular disc, printed-circuit antenna

Abstract: The resonant frequency is obtained in analytical form for a planar, circular disc antenna which is etched on a printed-circuit board so that the low-profile antenna is separated from the ground plane only by a thin layer of dielectric material. The formula is found to have an error of less than 2.5 percent when compared with experimental data.

A theoretical investigation of the rectangular microstrip antenna element

Abstract: A theoretical treatment of the rectangular microstrip radiating element has been performed. The element has been modeled as a line resonator with radiation taking place at the open-circuited ends. This has been verified by using a liquid crystal visual detector. With the simplified model, the input impedance and the far fields have been calculated for different resonant modes. The interaction between the radiating ends will effect the input impedance, and this has been considered by defining a mutual conductance. Also, a mutual conductance between microstrip elements has been expressed in far-field quantities and plotted as a function of spacing along the E - and H - planes. The directivity of an isolated element has been calculated as the directivity of one radiating end times the contribution due to the array factor.

Dissipation Loss Effects in Isolated and Coupled Transmission Lines

Abstract: This paper describes a computer-aided analysis of dissipation losses in uniform isolated or coupled transmission lines for microwave and millimeter-wave integrated-circuit applications. The analysis employs a quasi-TEM model for isolated transmission lines and for the even- and odd-mode transmission lines associated with coupled-line structures. The conductor and dielectric losses are then related to equivalent charge density distributions, which are evaluated using a method-of-moments solution. The transmission lines treated by this analysis may contain any number of Iossy conductors and inhomogeneous dielectrics, consisting of any number of different homogeneous dielectric regions. A development is provided to explicitly relate the four-port terminal-electrical performance of directional couplers to evaluated even- and odd- mode loss coefficients. Examples of evaluated losses are presented in graphical form for isolated lines of inverted microstrip and trapped inverted microstrip and edge-coupled microstrip with a dielectric overlay. The analysis accuracy has been confirmed using microstrip and coplanar waveguide configurations. A comparison is made of the total loss characteristics for microstrip, coplanar waveguide, inverted microstrip, and trapped inverted microstrip. Calculations are compared with measurements for the coupled-line structure. Accuracy of the solution and suggested refinements are discussed. Five computer programs are documented.

Multifrequency microstrip antenna

Abstract: Three spaced apart electrically conducting discs coaxially mounted with dielectric material therebetween, one outside disc forming a ground plane and the center disc being driven by a lead through the ground plane to form a first microstrip antenna resonant at a first frequency, and the center disc forming a ground plane for the other outside disc which if fed by a lead extending through both of the other discs on a plane of zero electrical field for the second plate and along a radius orthogonal with a radius through the first lead, to form a second microstrip antenna resonant at a second frequency.

Flush-mounted piggyback microstrip antenna

Abstract: A dual radiating system where one radiating element is placed atop the ot in a piggyback fashion. The elements can be a pair of microstrip or dielectric-loaded parallel plate radiators, or it can be a combination of the two. Separate coaxial lines feed each of the radiators, and there is a minimum of coupling from one antenna to another. The antenna can be used alone or more effectively in a linear or planar conformal array.

Windowed dual ground plane microstrip antennas

Abstract: Microstrip antenna systems having two ground planes spaced apart by a dietric substrate and radiating elements coplanar with one of the two ground planes, or sandwiched within the dielectric substrate separating the two ground planes adjacent a window in one of the ground planes. The two ground planes are shorted together in most instances, and the dual ground plane system provides a reduction in the leakage losses of transmission lines feeding and/or interconnecting the microstrip antenna radiating elements. The dual ground plane system also provides a reduction in coupling between arrayed radiation elements as well as an increase in bandwidth, in some instances.

Microstrip antennas and arrays. Part 1: Fundamental action and limitations

Abstract: Consideration of the radiation mechanism of an open-circuit microstrip termination indicates that the terminal-plane region is the dominant radiating aperture. On this basis, the radiation patterns of several types of microstrip radiating elements in rectangular and cylindrical geometry are calculated and substantiated by experiment. In general, the patterns exhibit the characteristics of slot radiators, thus endorsing the action of an end-radiating aperture; the radiation admittance of the latter is obtained by novel measurements of the standing waves in a truncated microstrip line but, when the substrate extends beyond the radiating aperture, substrate surface waves are generated. An analysis of the substrate waves indicates that the side-lobe level of an array of microstrip radiating elements could be limited to around -20 dB, and severe unwanted coupling effects between microstrip circuits are also noted. The use of substrate troughs to reduce the surface-wave generation is discussed, and a strip width-modulation technique proposed to control the array aperture distribution and simplify the feeding configuration. The implications of these present findings on the potential performance of microstrip antenna arrays is discussed and design recommendations made; the latter are investigated in a companion paper.

Loaded microstrip antenna with integral transformer

Abstract: A microstrip antenna design according to which the impedance matching transformer is contained in the area usually occupied entirely by the etched metal radiator.

Missile base mounted microstrip antennas

Abstract: Proof of the feasibility of aft mounting low-profile antennas on reentry vehicles is presented. This is an application of state of the art antenna hardware. Aft mounting presents the best reentry environment to antenna hardware, and its practicality has been demonstrated. Microstrip antenna principles can be used to produce very rugged antennas. Their low profile reduces many interface, mechanical, and survival problems. The pattern coverage for these vehicles must be toward the fore direction. This type of pattern requires an interaction between the vehicle and the antenna when the antenna is effectively shadowed from that direction. This paper describes the results obtained by actual experimental hardware. Contoured elements were used, as were foreshortened elements. These elements demonstrated ability to be fit around other aft equipment. The versatility of these elements were further demonstrated by tailoring them for two different types of coverage to accommodate different vehicle operational requirements.

Microstrip antennas and arrays. Part 2: New array-design technique

Abstract: Open-circuit terminations on half-wavelength stubs form the radiating elements in a new design technique for linear microstrip microwave arrays. Measured results, on computer-designed resonant and wideband travelling-wave arrays with broadisde beams, demonstrate the technique; the effects of corporate feeds and radomes are also considered. The computer design of medium gain arrays, with H-plane sidelobe levels below about -21 dB, demands characterisation of the microstrip T-junction with an accuracy that is currently unavailabe, and the dimensional precision has to be obtained by experimental means. It is concluded, to date, that the known extraneous sources of radiation do not inhibit the control of H-plane sidelobes to a level of at least -25 dB and the new design technique makes microstrip arrays highly competitive with their conventional waveguide counterparts.

High efficiency microstrip antenna structure

Abstract: A microstrip antenna wherein a cavity or channel is formed in the ground plane conductor to reduce radiation losses and cross-coupling between elements. A shielded embodiment is also disclosed.

Broadband microstrip disc antenna

Abstract: A broadband antenna including a conductive disc parallel to and spaced from a ground plane with dielectric material therebetween, the disc including a first sector of approximately 270° having a first diameter and the remaining sector having a second diameter different from the first so that the equivalent resonant structure of the antenna is essentially detuned to broaden the bandwidth thereof, and a cylindrical array of such antennas for providing a desired radiation pattern, generally omnidirectional.

Study of Microstrip Antennas, Microstrip Phased Arrays, and Microstrip Feed Networks.

Abstract: : Microstrip antennas are inherently narrow band devices with low efficiency On the other hand, they have many unique and attractive properties: they are low in profile, light in weight, compact and conformable in structure, and easy to fabricate and to be integrated with solid-state devices They are superior to the conventional flush-mount antennas since they are truly thin antennas, requiring no cavity backing There seems to be little doubt that they will find more and more applications as more compact efficient solid state sources, amplifiers, and self-matching networks are developed to compensate for the shortcomings In this investigation a simple and useful theory, based on the cavity model, has been developed to analyze and predict the fundamental behavior of microstrip antennas of various basic shapes In general, there is a good agreement between the theory and experiment

Dual asymmetrically fed electric microstrip dipole antennas

Abstract: Circularly polarized microstrip antennas consisting of thin electrically ducting, square-shaped radiating elements formed on one surface of a dielectric substrate and having a ground plane on the opposite surface of the substrate. Two feed points are used to provide a circular polarized radiation pattern. The feed points are located along the centerlines of the antenna length and width or along the diagonal lines of the element and the input impedances can be varied by moving the feed points along both centerlines or both diagonal lines from the centerpoint of the element. The antennas can be notched in from the edges of the radiating element along the centerlines of the element width and length, or along opposite diagonal lines of the element, to the optimum input impedance match feed point.

Microstrip feed with reduced aperture blockage

Abstract: A parabolic reflector is fed by a microstrip antenna supported at the focusy a tube aligned along the focal axis of the reflector. The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalties thereon or therefor.

Dual diagonally fed electric microstrip dipole antennas

Abstract: Circularly polarized microstrip antennas consisting of thin electrically ducting, square-shaped radiating elements formed on one surface of a dielectric substrate and having a ground plane on the opposite surface of the substrate. Two feed points are used to provide a circular polarized radiation pattern. The feed points are located along the centerlines of the antenna length and width or along the diagonal lines of the element and the input impedances can be varied by moving the feed points along both centerlines or both diagonal lines from the centerpoint of the element. The antennas can be notched in from the edges of the radiating element along the centerlines of the element width and length, or along opposite diagonal lines of the element, to the optimum input impedance match feed point.

Dual notch fed electric microstrip dipole antennas

Abstract: Circularly polarized microstrip antennas consisting of thin electrically ducting, square-shaped radiating elements formed on one surface of a dielectric substrate and having a ground plane on the opposite surface of the substrate. Two feed points are used to provide a circular polarized radiation pattern. The feed points are located along the centerlines of the antenna length and width or along the diagonal lines of the element and the input impedances can be varied by moving the feed points along both centerlines or both diagonal lines from the centerpoint of the element. The antennas can be notched in from the edges of the radiating element along the centerlines of the element width and length, or along opposite diagonal lines of the element, to the optimum input impedance match feed point.

Antenna coupling network with element pattern shift

Abstract: In any array antenna system having a coupling network interconnecting a plurality of element groups, the coupling network is provided with phase adjustments to shift the angular location of the effective element radiation pattern. An effective technique for this phase adjustment in a microstrip coupling network makes use of a field altering structure positioned adjacent the microstrip.

Design of Coupled Microstrip Lines (Letters)

Abstract: An accurate and direct method for designing coupled microstrip lines for any substrate is given once the design curves for any other substrate are known.

Microstrip antennas for millimeter waves

Abstract: Proof of the feasibility of low-cost conformal printed circuit board antenna arrays at millimeter wave frequencies is presented. It has become apparent that present day trends in microwave systems are indicating extensive design efforts in the millimeter wave region. Many proposed systems will be seriously hindered by a lack of readily available inexpensive components. Microstrip conformal antennas have distinct advantages in cost, variety of field pattern, and reproducibility for microwave system design. It is felt that similar advantages could be realized at millimeter wave frequencies. The results obtained with actual experimental hardware are described. Discussed are 4 \times 4 element arrays operating in the 35- and 60-GHz regions and a 32 \times 32 element array operating near 38 GHz.

Cross Fed Printed Aerials

Abstract: The design of a simple printed planar array to replace horns in short range domestic radar and traffic control systems is described. The essential criterion is to keep the basic material and processing costs low, whilst retaining a necessary specified aerial performance. Cross-fed aerials use a novel diagonal fed array of microstrip radiating elements to control the beamwidth and side lobe levels, together with fibreg1ass or polymer materials and photoetching techniques to keep the cost low. Good efficiencies for frequencies up to 14GHz have been demonstrated with aerial gains from 10 to 25dB.

Microstrip coupling to slotted conductor - uses microstrip branches for power dividing to ensure optimum energy transfer

Abstract: The coupling of a microstrip to a slotted conductor is made by placing them at right angles to each other, the division of power between the two sides of the conductor being achieved with a T-type junction or with a hybrid junction. The crossing points of the slotted conductor with the two branches of the microstrip are offset by a quarter wavelength. In practice, the couplings (10, 11) of the microstrip (5) prevent reflection by the inclusion of a balancing resistance (12) between the ends of leads (6, 7) of the microstrip. The 180 deg. phase difference between the two branches is due to a quarter-wavelength side (16), while in the mixer diode (2) of the waves are in phase for addition. The length of side (16) as well as the length of couplings (10, 11) determine the ratio of power flow in the two branches.

Circular microstrip antennas

Abstract: The circular microstrip antenna is analyzed by developing the field equations within the antenna in terms of Bessel functions. When the order of the Bessel functions is 1, the antenna radiates normal to the surface on which the antenna is mounted. Equations are developed for calculation of radiation patterns, impedance, bandwidth and efficiency when the antenna is operating in this mode. Curves are provided to assist in the design of a circular microstrip antenna.

Directive Microstrip Antennas

Abstract: Planar, directive, X band antennas were constructed with wide microstrips printed on phainolic paper substrates. Every microstrip functions as a cavity with loses due to radiation from the slots formed between their wide edjes and the earth plane. A number of approximations, mentioned below, form the theory of their opperation. A way is given to cancel out the effect of the fringe capacitance of the microstrip edges on the tunning of the cavity, and a simple way to feed two radiating strips in tandem.