A spiral antenna, comprising a first arm and a second arm. The first arm and second arm are interlaced with each other. Each arm has a plurality of turns comprising an inner subset of circular turns, and an outer subset of turns, electrically coupled to the inner subset, having a shape with only four lines of symmetry. An array of such spiral antennas disposed a substrate that extends in a direction of a longitudinal axis and having a round cross section in a plan transverse to the longitudinal axis.

An antenna 10 comprises a single wire wound in a helix 12 comprising a plurality of turns 1, 2, 3, n, n+1, . . . p around a main axis 11 with immediately adjacent turns having an inter-turn spacing between them. The helix has a back end 14 and a front end 16 and the main axis defines a main beam direction. A transverse crosssectional area of the helix monotonously decreases from the back end 14 to the front end 16. The inter-turn spacing S.sub.1 . . . S.sub.n . . . monotonously decreases from the backend 14 to the front end 16. A feed-point 13 is provided at the back end 14.

Provided herein is a deployable antenna assembly, a method of deploying an antenna, and systems and methods for sequentially deploying an extendable structure. The deployable antenna assembly includes an extendable pillar configured to extend in an axial direction along a deployment axis of the deployable antenna assembly to deploy an antenna. The extendable pillar includes at least one extendable element configured to convert between a stowed configuration and a deployed configuration where the deployed configuration is longer in the axial direction than the stowed configuration. The extendable pillar also includes a launcher configured to initiate conversion of the plurality of extendable elements from the stowed configuration to the deployed configuration, thereby extending the extendable pillar and deploying the antenna.

A demultiplexer/multiplexer includes an input terminal, which receives input signals from respective phases of a quadrifilar helix antenna; phase shifter/separator/mixers, which alternately phase-shift right-handed and left-handed circularly polarized waves of the input signals, respectively, by 90/90 to produce phase-shifted waves to be combined in an inphase combination; phase shifter/mixers, which receive the left-handed or right-handed circularly polarized waves from the phase shifter/separator/mixers, and phase-shift one of the left-handed and right-handed circularly polarized waves by 180/180 to produce a phase-shifted wave to be combined with the other of the left-handed and right-handed circularly polarized waves in an antiphase combination; a variable phase shifter, which adjusts an output signal from the phase shifter/mixers by a phase-shift amount that is received in advance; and an output terminal, which outputs an output signal from the variable phase shifter and the other output signal that is not input to the variable phase shifter.

Example apparatuses and methods relating to antennas are provided. An example apparatus in the form of an antenna assembly includes a first conductor structurally formed into a plurality of first conductor structural waves and a second conductor structurally formed into a plurality of second conductor structural waves. The first conductor and second conductor may be helically wound to form a bifilar helix structure having a proximal end and a distal end. The first conductor and the second conductor may be operatively coupled at the proximal end of the bifilar helix structure to form a signal feed point, and the first conductor and the second conductor are operatively coupled at the distal end of the bifilar helix structure to form a load point.

Aspects of the subject disclosure may include, for example, a launching device including a transmitter configured to generate a radio frequency signal in a microwave frequency band. A helical antenna is configured to launch the radio frequency signal as a guided electromagnetic wave that is bound to an outer surface of a transmission medium, wherein the guided electromagnetic wave propagates along the outer surface of the transmission medium without an electrical return path. Other embodiments are disclosed.

An electromagnetic wave irradiation apparatus includes a housing having a hollow portion formed inside and an open lower side; a coil-type antenna with a spiral shape in the hollow portion and configured to emit electromagnetic waves; a window coupled to the open lower side of the housing; and a capacitance variation measurement unit configured to measure a capacitance variation of the coil-type antenna. The electromagnetic wave irradiation apparatus may further include a cooling unit configured to cool at least one of the window or the housing. The capacitance variation measurement unit includes a capacitance sensor with one side connected to the coil-type antenna and the other side connected to the ground.

Novel and advantageous antennas are provided. A multi-functional antenna can morph in order to change geometrical shape and thereby change its antenna radiation characteristics. Such characteristics can include radiation pattern, bandwidth, beamwidth, operational frequency, and directivity. The antenna can therefore be multifunctional such that one single antenna can serve multiple applications.

In the field of circular-polarized planar wire antennas for very wide band telecommunications systems, and an antenna reflector for such an antenna, an antenna device comprises an antenna reflector and an antenna, and a method for implementing the antenna reflector. The antenna reflector comprises, on the one hand, a first reflection region exhibiting electromagnetic properties of an electrical conductor in a first sub-band of frequencies and, on the other hand, a second reflection region exhibiting electromagnetic properties akin to a magnetic conductor in a second sub-band of frequencies. Each reflection region is designed to face a region of the antenna able to emit electromagnetic radiation in the corresponding sub-band of frequencies in order to reflect the electric field of the backward radiation in phase with the electric field of the forward radiation.

Embodiments disclosed herein show a novel helical meandered antenna, wherein some embodiments feature tunability through the application of DC voltage to switch and connect multiple antenna arms. The design, successfully fabricated and tested for wireless applications, exhibits a compact size and omnidirectional radiation pattern. The use of diodes as effective components for tunability is explored, allowing adjustments in the operating frequency of the helix. Extensive simulations and measurements were conducted on over 15 different antenna designs, showing consistent results. The proposed helical antenna demonstrates a fine-tunable operation frequency change from 459 MHz to 338 MHz (over 30% change) with low voltage supplied DC from 0 V to 1.5 V.