Tdk Corporation

Tdk Rf Solutions, Inc.

Emc Automation, Inc.

Tactical Systems Research, Inc.

James Stuart McLean

Gentry Elizabeth Crook

Robert Sutton

Nobutaka Misawa

Kunio Yata

Hidetsugu Sakou

Gentry Crook

A biconical antenna driven by an equal-delay transformer is provided herein with a bifurcating ground plane. According to one embodiment, the biconical antenna comprises a pair of cone-shaped elements and a conducting ground plate. The cone-shaped elements are arranged back-to-back to one another and aligned along a first axis. The conducting ground plate is arranged between the cone-shaped elements in a plane perpendicular to the first axis. As described herein, the bifurcating ground plane provides the decoupling needed to eliminate the anomalous undulations, which tend to occur in the antenna response at odd-integer average quarter-wave frequencies.

Biconical antenna with equal delay balun and bifurcating ground plane

An end-fed sleeve dipole is provided herein with improved impedance match and increased bandwidth by incorporating a &#xbe;-wavelength transformer in the antenna design. The &#xbe;-wavelength transformer is compatible with a number of different choking schemes, including but not limited to, a single &#xbc;-wave choke sleeve, a single &#xbc;-wave choke sleeve with additional ferrite beads, and two or more &#xbc;-wave choke sleeves with or without ferrite beads. In some embodiments, one or more shunt resonators may be used to provide additional impedance compensation.

End-fed sleeve dipole antenna comprising a &#xbe;-wave transformer

A Bulk Current Injection (BCI) transformer is provided herein with a magnetic core and a plurality of windings. The magnetic core is configured for encircling one or more electrical conductors under test. Each of the plurality of windings are wrapped, at least in part, around a longitudinal dimension of the magnetic core and spaced apart around an azimuthal dimension of the magnetic core. During injection tests, a power source may be coupled for supplying current to each of the windings at a respective 'feed point.' Arranging multiple feed points around the magnetic core enables current flow through the windings to generate an azimuthally-uniform magnetic flux density in the magnetic core. The uniform magnetic flux density enables the BCI transformer to excite only common mode currents in the electrical conductors under test. BCI test methods, including injection tests and current sensing tests are also provided herein, along with a test setup for characterizing BCI transformers.

Bulk current injection (BCI) probe with multiple, symmetrically spaced feeds

A dual- or quad-ridged horn antenna with an embedded impedance matching network is provided herein. According to one embodiment, the horn antenna may include at least one pair of ridges arranged opposite one another for guiding an electromagnetic wave there between. A transmission line is coupled to a first one of the ridges for supplying power to, or receiving a signal from, a feed region of the horn antenna. To reduce impedance mismatches between the transmission line and the ridges, an impedance matching network is embedded within a second one of the ridges at the feed point. The impedance matching network reduces impedance mismatch and extends the operational frequency range of the horn antenna by providing a sufficient amount of series capacitance between the transmission line and the ridges at the feed region. As set forth herein, the impedance matching network is preferably implemented as an open-circuit transmission line stub or capacitive stub.

Horn antenna with integrated impedance matching network for improved operating frequency range

A dipole antenna is provided herein with improved performance at a lower end of the antenna's operating frequency range. According to one embodiment, the dipole antenna may include a plurality of antenna elements coupled to impedance transformer via a pair of cones and a pair of ears. The dipole antenna may also include a high-pass matching network specifically configured to improve antenna performance at the lower end of the operating frequency range. For example, a first stage of the matching network (i.e., closest to the antenna elements) may include two series capacitors, while a second stage of the matching network (i.e., furthest from the antenna elements) includes an inductor coupled in shunt between the two capacitors.

Dipole antenna with improved performance in the low frequency range

An improved E-field generator including a slow-wave transmission line structure is provided herein. In some cases, the improved E-field generator may include an inductively-loaded slow-wave transmission line structure driven by a power source at one end of the structure and terminated by a load at the other end of the structure. In other cases, the improved E-field generator may include a capacitively-loaded slow-wave transmission line structure. In either case, the improved E-field generator provides a frequency-independent, significantly increased electric field at a distance spaced from the generator without altering the dimensions of the generator and/or the input power supplied to the generator. The increase in generated field intensity is achieved by decreasing the phase velocity of the electromagnetic wave propagating along the parallel elements of the generator.

Electric field generator incorporating a slow-wave structure

A log periodic dipole array (LPDA) antenna including a first antenna element, a second antenna element and a pair of transmission line structures is provided herein. The first antenna element is fabricated as a continuous piece of conductive material to include a plurality of dipole elements extending outward from a center conductor. The second antenna element is fabricated in the same manner, albeit a mirror image, of the first antenna element. In one embodiment, the antenna elements are fabricated by cutting a contour of the plurality of dipole elements and the center conductor from a sheet of metal (e.g., aluminum or one of its alloys). The antenna elements and transmission line structures are preferably coupled, such that no electrical discontinuities exist between the antenna elements and a respective transmission line structure. In one embodiment, a conductive epoxy or a brazing process is used to permanently attach flat bottom surfaces of the transmission line structures to a different center conductor of the first and second antenna elements.

Log-periodic dipole array (LPDA) antenna and method of making

A low-loss, high-efficiency, broadband antenna including both electric and magnetic dipole radiators is provided herein. The broadband antenna may be referred to as a 'P&#xd7;M antenna' and may generally include a ground plane; a magnetic radiator formed within the ground plane; a conductive feed arranged within a first plane, which is parallel to the ground plane; and an electric radiator arranged within a second plane, which is perpendicular to the ground plane and coupled at one end to the conductive feed. According to a particular aspect of the invention, the electric and magnetic radiators are substantially complementary to one another and are coupled for producing a P&#xd7;M radiation pattern over a broad range of operating frequencies. One advantage of the P&#xd7;M antenna described herein is that the complementary antenna elements are combined without the use of a lossy, resistive matching network, thereby increasing the efficiency with which the P&#xd7;M radiation pattern is produced.

PxM antenna with improved radiation characteristics over a broad frequency range

A broadband antenna including both electric and magnetic dipole radiators is provided herein. The broadband antenna may be referred to as a 'P&#xd7;M antenna' and may include a pair of magnetic loop elements, each having multiple feed points symmetrically spaced around the loop element. The broadband antenna may also include an electric dipole element arranged between the pair of magnetic loop elements. In general, the electric dipole element and the magnetic loop elements may be coupled together through a network of transmission lines, as opposed to being incorporated into a single radiative element.

PxM antenna for high-power, broadband applications

As provided herein, a dual- or quad-ridged broadband horn antenna may include a pair of conductive antenna elements arranged opposite one another for guiding an electromagnetic wave in a longitudinal direction through the horn antenna. In some cases, the pair of conductive antenna elements may include substantially convex inner surfaces and appropriately shaped outer surfaces. The convex inner surfaces may generally function to direct or guide the radiated energy without disturbing the intended radiation pattern. To maintain the intended radiation pattern, the broadband horn antenna may also include a pair of tapered extension elements, each coupled to an outer surface of a different one of the antenna elements at one end thereof. In some cases, a magnetic material may be arranged upon at least a portion of the antenna elements to restrict surface currents to flowing along the inner surfaces only. In some cases, longitudinal grooves may be formed within the inner surfaces to restrict surface currents from flowing in a direction transverse to the longitudinal direction.

Dual- and quad-ridged horn antenna with improved antenna pattern characteristics

A conductive member may include a conductor having a pair of opposed parallel surfaces and a cable guide arranged inside the conductor. In another embodiment, a conductive member may include a conductive bar having a pair of opposed parallel surfaces and a convex surface connecting respective first ends of the pair of opposed parallel surfaces to one another. An embodiment of a method for forming a conductive member includes forming a cable guide arranged inside a conductor having opposed parallel surfaces, where the cable guide is oriented in a direction substantially parallel to the opposed parallel surfaces. In an embodiment of an antenna, the antenna includes a conductor having a pair of opposed lateral surfaces, and a cable guide arranged inside the conductor and oriented in a direction substantially parallel to that of the opposed parallel surfaces.

Transmission line conductor for log-periodic dipole array

The present invention provides a metrology antenna system that combines a sleeve dipole antenna having two coaxial input ports with a balancing network. This combination (1) minimizes or eliminates spurious radiation from the balancing network (2) provides for a symmetric pair of feed regions which may be made arbitrarily small, and (3) provides for an essentially perfect impedance match to a broad range of resistive source impedances. The present invention provides a fabrication of arbitrarily small feed regions such that dipoles can be realized at high frequencies at little manufacturing cost.

Metrology antenna system utilizing two-port, sleeve dipole and non-radiating balancing network

An antenna includes a conductive loop with multiple feed points spaced around the loop. The loop may be opened at each feed point, thereby forming multiple loop portions. In an embodiment, the antenna may be a shielded loop antenna having multiple shielded feed lines. A kit including one or more components of such a shielded loop antenna may include a conductive structure in the form of a loop having multiple radial arms. In an embodiment of a method for forming an antenna, multiple feed points may be spaced apart around a conductive loop, and a respective feed line coupled to each of the feed points. In an embodiment, the feed lines may be shielded lines connected together at a shunt connection. The antenna may produce an isotropic radiation pattern similar to that of an electrically small antenna, but from an antenna of moderate electrical size.

Multiply-fed loop antenna

A transformer for connection between a generator and a load may be formed by connecting n transmission lines together, in series at one end and in parallel at the other end. The transmission lines are configured to each have a characteristic impedance of {square root over (R +L &verbar;Z +L (f +L &verbar;)}, where f is the frequency at which each transmission line is one quarter of a wavelength long (quarter-wavelength frequency), &verbar;Z (f )&verbar; is the magnitude of the load impedance at the quarter-wavelength frequency, and R is the generator resistance. The transformer exhibits a frequency-dependent impedance transformation ratio, allowing a more efficient impedance match of a generator to a load having a frequency-dependent impedance, such as an antenna.

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Austin, TX, United States of America

James Stuart McLean