Abstract: Systems and methods for enhanced antenna isolation are disclosed. An example antenna isolation system includes a first antenna element of an antenna array configured to transmit or receive wireless transmissions, a second antenna element of the antenna array adjacent to the first antenna element in the antenna array, and a scattering structure disposed substantially between the first and second antenna elements. The scattering structure is configured to reduce electromagnetic coupling between the first and second antenna elements by, at least in part, directing electromagnetic radiation coupled through the first antenna element away from the second antenna element.

Abstract: A spacecraft communications payload includes a beam forming network (BFN), wherein the BFN includes a first feed waveguide and a first set of branch waveguides, each branch waveguide in the first set operating in a frequency band having a characteristic waveguide wavelength ?g1. A proximal portion of the first set of branch waveguides is communicatively coupled with the first feed waveguide. A distal portion of the first set of branch waveguides is communicatively coupled by way of an array of slots with a plurality of radiating elements. A separation distance between adjacent slots in the array is approximately equal to ?g, and the array of slots is configured as a honeycomb-like triaxial lattice. In some implementations, a compact BFN may be configured to simultaneously operate at two different polarizations (“dual-polarized”) and/or frequency bands (“dual-band”).

Abstract: An orthomode transducer (OMT) configured as a compact three port septum polarizer waveguide where one of the three ports is configured to propagate linear orthogonally polarized signals, and an edge of the septum facing that port has a profile including three or more segments with respective facing edges spaced at diverse respective distances from the one of the three ports that is configured to propagate linear orthogonally polarized signals. The three or more segments include one or both of a notch and a protrusion.

Abstract: Systems and methods for enhanced antenna isolation are disclosed. An example antenna isolation system includes a first antenna element of an antenna array configured to transmit or receive wireless transmissions, a second antenna element of the antenna array adjacent to the first antenna element in the antenna array, and a scattering structure disposed substantially between the first and second antenna elements. The scattering structure is configured to reduce electromagnetic coupling between the first and second antenna elements by, at least in part, directing electromagnetic radiation coupled through the first antenna element away from the second antenna element.

Abstract: A spacecraft communications payload includes a beam forming network (BFN), wherein the BFN includes a first feed waveguide and a first set of branch waveguides, each branch waveguide in the first set operating in a frequency band having a characteristic waveguide wavelength ?g1. A proximal portion of the first set of branch waveguides is communicatively coupled with the first feed waveguide. A distal portion of the first set of branch waveguides is communicatively coupled by way of an array of slots with a plurality of radiating elements. A separation distance between adjacent slots in the array is approximately equal to ?g, and the array of slots is configured as a honeycomb-like triaxial lattice. In some implementations, a compact BFN may be configured to simultaneously operate at two different polarizations (“dual-polarized”) and/or frequency bands (“dual-band”).

Abstract: A mode filter provides a low-loss transmission path for RF signals propagating in a first mode, while substantially suppressing at least one second mode. The mode filter includes a proximal port and a distal port, having a respective characteristic cross sectional dimension Dp1 and Dp2, and an electrically conductive hollow tube having a longitudinal axis that extends a length L between a distal end of the proximal port and a proximal end of the distal port. A cross section transverse to the longitudinal axis is non-uniform along length L and has a minimum internal characteristic dimension Dmin at least at a first longitudinal position and a maximum internal characteristic dimension Dmax at least at a second longitudinal position. The mode filter is configured to suppress the at least one second mode by at least 5 dB, and Dmax is less than 2.5 times the greater of Dp1 and Dp2.

Abstract: A wide beam radio frequency (RF) antenna includes a waveguide and one or more electrically conductive protrusions. The waveguide has at least one electrically conductive interior wall surface, a boresight defined by a longitudinal axis, and an aperture plane, transverse to the longitudinal axis, disposed at a distal end of the waveguide. A first proximal portion of each protrusion is electrically coupled to the electrically conductive interior wall surface, a distal portion of the protrusion being outside the aperture plane.

Abstract: A mode filter provides a low-loss transmission path for RF signals propagating in a first mode, while substantially suppressing at least one second mode. The mode filter includes a proximal port and a distal port, having a respective characteristic cross sectional dimension Dp1 and Dp2, and an electrically conductive hollow tube having a longitudinal axis that extends a length L between a distal end of the proximal port and a proximal end of the distal port. A cross section transverse to the longitudinal axis is non-uniform along length L and has a minimum internal characteristic dimension Dmin at least at a first longitudinal position and a maximum internal characteristic dimension Dmax at least at a second longitudinal position. The mode filter is configured to suppress the at least one second mode by at least 5 dB, and Dmax is less than 2.5 times the greater of Dp1 and Dp2.

Abstract: A wide beam radio frequency (RF) antenna includes a waveguide and one or more electrically conductive protrusions. The waveguide has at least one electrically conductive interior wall surface, a boresight defined by a longitudinal axis, and an aperture plane, transverse to the longitudinal axis, disposed at a distal end of the waveguide. A first proximal portion of each protrusion is electrically coupled to the electrically conductive interior wall surface, a distal portion of the protrusion being outside the aperture plane.

Abstract: A radio and antenna system has a first microwave radio, second microwave radio, a first antenna and a dual mode coupler that has a first dual mode transmission line extending between a first port and a third port and a second dual mode transmission line extending between a second port and a microwave absorbing termination. The first microwave radio is coupled to the first port. The second microwave radio is coupled to the second port. The antenna is coupled to the third port. The first dual mode transmission line is coupled to the second dual mode transmission line so that microwave signals in either of the first dual mode transmission line and the second dual mode transmission line propagates microwave signals in the other of the first dual mode transmission line and the second dual mode transmission line.

Abstract: A radio and antenna system has a first microwave radio, second microwave radio, a first antenna and a dual mode coupler that has a first dual mode transmission line extending between a first port and a third port and a second dual mode transmission line extending between a second port and a microwave absorbing termination. The first microwave radio is coupled to the first port. The second microwave radio is coupled to the second port. The antenna is coupled to the third port. The first dual mode transmission line is coupled to the second dual mode transmission line so that microwave signals in either of the first dual mode transmission line and the second dual mode transmission line propagates microwave signals in the other of the first dual mode transmission line and the second dual mode transmission line.

Abstract: A monopole-type antenna (10) for multi- or wide-band use to transmit or receive radio frequency electromagnetic energy. A feed point (12) provides energy into the antenna or receives energy from the antenna. A driven radiating section (16) includes a first top-loading element (22) and a feed conductor (20) that electrically connects the feed point linearly to the first top-loading element, yet with the driven radiating section not electrically connected to a grounding surface (14). A parasitic radiating section (18) includes a second top-loading element (26) and a bridge conductor (24) that electrically connects the second top-loading element linearly to the grounding surface When energy is then provided at the feed point and conducted to the driven radiating section, it produces a first resonance mode, coupling at least some of the energy into and exciting the parasitic radiating section to produce a second resonance mode.

Abstract: An antenna particularly suitable for use in radio frequency identification (RFID) transponders. First and second half portions each include nominally straight conductive sections primarily defining a radiating characteristic and nominally spiral conductive sections creating a positive reactive characteristic of the antenna. The straight conductive sections have feed points for connecting the antenna into the RFID transponder, and further connect with the respective spiral conductive sections. The first and said second half portions characterize the antenna as being a dipole type, and adding an optional loop section connecting the straight conductive sections can further characterize it as being of a folded dipole type.

Abstract: An antenna (10) having a top (14), a bottom (16), and a longitudinal axis (20). An outer shell (12) of electrically conductive material is provided which is coaxial with the longitudinal axis, and which includes an outer top wall (22) joining with an outer side wall (24) that extends toward the bottom of the antenna. The shell defines an interior region (18) that is filled with a dielectric material, and the shell has at least one slot (30) with opposed slot ends. Each slot extends from one opposed slot end in the side wall, and at least partially across the top wall to an opposed other slot end. A coaxial feed (32) extends from the bottom of the antenna to the top of the antenna, to convey electromagnetic energy to or from the top wall of the antenna.

Abstract: An antenna. A base body made of a dielectric material is provide, wherein the base body has a bottom surface and an opposed top surface. A conductive layer of a conductive material is provided on the bottom surface of the base body. Two dipole conductors are provided that form a dipole on the top surface of the base body, wherein the dipole conductors are at least partially spiral shaped and have opposite directions. A balun is provided that has a feed conductor section and two ground conductor sections that are all substantially parallel. The balun receives an unbalanced signal from a feed line, transforms this signal, and provides it to the dipole conductors via the feed and ground conductor sections.

Abstract: A monopole-type antenna (10) for multi- or wide-band use to transmit or receive radio frequency electromagnetic energy. A feed point (12) provides energy into the antenna or receives energy from the antenna. A driven radiating section (16) includes a first top-loading element (22) and a feed conductor (20) that electrically connects the feed point linearly to the first top-loading element, yet with the driven radiating section not electrically connected to a grounding surface (14). A parasitic radiating section (18) includes a second top-loading element (26) and a bridge conductor (24) that electrically connects the second top-loading element linearly to the grounding surface When energy is then provided at the feed point and conducted to the driven radiating section, it produces a first resonance mode, coupling at least some of the energy into and exciting the parasitic radiating section to produce a second resonance mode.

Abstract: An antenna particularly suitable for use in radio frequency identification (RFID) transponders. First and second half portions each include nominally straight conductive sections primarily defining a radiating characteristic and nominally spiral conductive sections creating a positive reactive characteristic of the antenna. The straight conductive sections have feed points for connecting the antenna into the RFID transponder, and further connect with the respective spiral conductive sections. The first and said second half portions characterize the antenna as being a dipole type, and adding an optional loop section connecting the straight conductive sections can further characterize it as being of a folded dipole type.

Abstract: An antenna having a cylindrical shaped dielectric core region that defines top, bottom, and side surfaces. Two laterally opposed conductive linking tracks are provided at the top or bottom surface and connect to respective groups of conductive antenna elements which extend across the top (or bottom surface) and at least partially down (or up) the side surface. A balun having two input terminals and two output terminals is provided at the top (or bottom) surface such that a feed line having two conductors extending from outside of the antenna connect respectively to the input terminals and the output terminals each connect respectively to a linking track.

Abstract: A planar antenna having top and bottom nominally planar conductors that are oriented substantially planarly parallel and form an antenna interior region. The top conductor includes two radiating conductors each having an inner end and a distal end. A feed extends from outside of the planar antenna, through the antenna interior region, and to the top conductor. The feed includes a balun and has a first feed conductor that connects to the inner end of the first radiating conductor and a second feed conductor that connects to the inner end of the second radiating conductor.

Abstract: A mode transducer for converting an electromagnetic wave between TE1,0 and TM0,1 modes. A rectangular waveguide guides the wave while in TE1,0 mode and a circular waveguide guides the wave while in TM0,1 mode. The rectangular waveguide and the circular waveguide are joined by a chamber to form a right angle structure. The chamber particularly includes offset walls distended away from proximal portions of the rectangular waveguide to convert the electromagnetic wave between modes. Two of the mode transducers rotatably coupled with a suitable rotation mechanism may be used as a rotary waveguide joint.