The reconfigurable MIMO and sensing antenna system combines a 2-element reconfigurable MIMO antenna system with a UWB element. The complete setup is suitable for CR platforms that require sensing UWB band availability. The design is planar in structure and includes a pair of PIFAs disposed on a dielectric substrate top surface. The UWB sensing element is disposed on the dielectric substrate bottom surface. An F-head portion of each PIFA has two arms extending to a longer peripheral edge of the substrate. An F-tail portion of each PIFA extends from the substrate's shorter peripheral edge. The two PIFAs are mirror images of each other. For each PIFA, three diode circuits include a PIN diode in combination with a varactor diode connected to and extending away from the F-tail portion of the PIFA, thereby creating separate radiating branches of the PIFA.

Various methods, apparatus, devices and systems are provided for electrically short antennas for efficient broadband transmission. In one example, among others, a system includes a segmentally time-variant antenna and a segment controller that can control conductivity of individual segments of the segmentally time-variant antenna. The conductivity of the individual segments is modulated to allow a pulse to propagate from the proximal end to the distal end of the segmentally time-variant antenna and impede a reflection of the pulse from propagating back to the proximal end of the segmentally time-variant antenna. In another embodiment, a method includes injecting a pulse at a first end of a segmentally time-variant antenna and modulating conductivity of individual segments to allow the pulse to propagate to a second end of the segmentally time-variant antenna and impede a reflection of the pulse from propagating back to the first end.

A multi-function array is described where several communication system functions are realized using the same antenna architecture. An array of antenna elements where each antenna element can generate multiple radiation patterns is described; the multiple radiation patterns from each antenna element provides increased capability and flexibility in generating a phased array, a MIMO antenna system, a receive diversity antenna system, as well as direction finding feature by way of an interferometer function provided by one or multiple elements. The small volume attributes of the antenna elements populating the array lend this technique to mobile wireless devices as well as access points.

A design for high-efficiency broadband antennas which includes a D-plate and an E-cylinder, electrically insulated from each other, the E-cylinder being above the D-plate, and both parts insulated from a ground plane. The E-cylinder and D-plate may be fed by distinct feed networks with adjustable impedance.

A variable resonant circuit is inserted between a feeding point of a radiating element and a ground conductor. When the variable resonant circuit is not inserted, an input impedance of the radiating element is lower than about 50 and capacitive in a first low frequency band, lower than about 50 and inductive in a second low frequency band, and close to about 50 in a high frequency band. When the variable resonant circuit exhibits a first resonance characteristic, the variable resonant circuit is inductive in the first low frequency band, and its impedance in the high frequency band is higher than that in the first low frequency band. When the variable resonant circuit exhibits a second resonance characteristic, the variable resonant circuit is capacitive in the second low frequency band, and its impedance in the high frequency band is higher than that in the second low frequency band.

This antenna array includes at least one primary antenna, at least one secondary antenna and at least one load coupled to a secondary antenna. The load includes two separate components, a first component being a resistor and a second component being selected from an inductor or a capacitor. The antenna array can include one or more of the following characteristic features, taken into consideration individually or in accordance with any technically possible combinations: the first component has negative resistance; the second component has negative inductance or a negative capacitance; at least one load has an adjustable impedance. The antenna array may be used in a system, such as a vehicle, a terminal, a mobile telephone, a wireless network access point, a base station, or a radio frequency excitation probe.

An antenna structure includes a main antenna, a parasitic antenna, a matching circuit and a switching circuit. The main antenna includes a feeding strip and a first radiating strip coupled to the feeding strip. The parasitic antenna includes a grounding strip and a second radiating strip coupled to the grounding strip. The second radiating strip is positioned adjacent to and apart from the first radiating strip, and further configured to electromagnetically couple to and be parasitically fed by the first radiating strip. The parasitic antenna and main antenna cooperatively generate at least one high-frequency resonate mode and a low-frequency resonate mode. The matching circuit is electronically coupled to the feeding strip. The switching circuit is electronically coupled to the matching circuit, and configured to regulate an inductance value of the matching circuit output to the feeding strip, thereby regulating a central frequency of the low-frequency resonate mode.

Disclosed are various embodiments of systems and methods for transmitting guided surface waves that illuminate a defined region. In one embodiment, such a method comprises installing a plurality of guided surface waveguide probes across a defined region having set boundaries, and setting respective frequency values of operation for the plurality of guided surface waveguide probes that allow for respective service areas to be defined that in the aggregate cover the defined region with guided surface waves.

Disclosed are various embodiments of a guided surface waveguide transmit system. One embodiment of the guided surface waveguide transmit system includes a guided surface waveguide probe configured to transmit a guided surface wave along a lossy conducting medium. The system further includes a controller device configured to receive load status data and signal for the guided surface waveguide probe to adjust transmission of the guided surface wave based at least in part on the load status data.

Introduced here is an ingestible device that can comprise a capsule, an intervention tool, and a processor configured to controllably employ the intervention tool to manipulate structures in a living body. The ingestible device may further comprise a camera that is configured to generate images of various in vivo environments as the ingestible device traverses the living body. These images may be wirelessly transmitted to an electronic device located outside of the living body to enable greater control over the intervention tool.