Abstract: An RF bandpass filter includes a cascaded series of a first subfilter and a second subfilter. Each subfilter includes a respective inverter, voltage-controlled capacitor and inductor. A first selected one of the first subfilter and the second subfilter is a pseudo low pass filter and a second selected one of the first subfilter and the second subfilter is a pseudo high pass filter. The RF bandpass filter is configured to separately control a bandwidth and center frequency of output RF energy. The bandwidth may be controlled to be substantially fixed over a significant substantial range. The center frequency and bandwidth are controlled by adjusting a voltage input to one or more of the voltage-controlled capacitors.

Abstract: A dual mode dielectric resonator (DR) filter has a first DR, and is configured to operate at a HE12? mode within a first frequency band while exhibiting a Q factor of no less than 5000. A first characteristic size of the first DR may be substantially similar to a size of a second DR, where the second DR is configured to operate in a conventional DR filter at a HE11? mode within a second frequency band, the second frequency band being substantially lower than the first frequency band.

Abstract: A multi-cavity RF filter has at least one electrically conductive coupling probe disposed between two resonator cavities. The coupling probe is provided with an ESD protective arrangement such that the coupling probe is electrically connected to a metallic housing of the RF filter only by the ESD protective arrangement. The ESD protective arrangement is configured to provide (i) a low resistance electrical path from the coupling probe to the metallic housing and (ii) a high impedance to RF energy having wavelengths proximate to a center frequency wavelength of the RF filter.

Abstract: A resonant circuit, configured to operate at a resonant frequency, includes a first arrangement providing a first equivalent capacitance ‘C’ and a second arrangement providing a first inductance. The first arrangement includes a quantity of ‘n’ capacitive elements connected in parallel, n being at least two, each of the n capacitive elements having a nominal capacitance approximately equal to C/n. The resonant frequency may exceed 1 GHz, the first equivalent capacitance may be at least 3 pF, and a composite Q factor of the first arrangement may be greater than 800. Whereas a single capacitive element having a capacitance of C may exhibit a Q factor equal to ‘Q1’, the composite Q factor of the first arrangement may be equal to ‘Q2’ where Q2 is substantially higher than Q1.

Abstract: A multi-cavity RF filter has at least one electrically conductive coupling probe disposed between two resonator cavities. The coupling probe is provided with an ESD protective arrangement such that the coupling probe is electrically connected to a metallic housing of the RF filter only by the ESD protective arrangement. The ESD protective arrangement is configured to provide (i) a low resistance electrical path from the coupling probe to the metallic housing and (ii) a high impedance to RF energy having wavelengths proximate to a center frequency wavelength of the RF filter.

Abstract: A dual mode dielectric resonator (DR) filter has a first DR, and is configured to operate at a HE12? mode within a first frequency band while exhibiting a Q factor of no less than 5000. A first characteristic size of the first DR may be substantially similar to a size of a second DR, where the second DR is configured to operate in a conventional DR filter at a HE11? mode within a second frequency band, the second frequency band being substantially lower than the first frequency band.

Abstract: An antenna system includes a helical antenna that includes one or more helically shaped conductors. Each conductor is substantially embedded in a dielectric structure.

Abstract: A power combining system includes multiple amplifiers, a reactive combiner for combining the output power of the amplifiers and a short plate. Switches are used to electrically connect an output of each of the amplifiers to an input of the reactive combiner. In the event of amplifier failure, the switches are used to electrically connect the short plate to an input of the reactive combiner in place of the failed amplifier.

Abstract: A patch filter element has an electrically-insulating substrate with an electrically conductive region on a first surface of said substrate, and a slot such as a crossed slot dividing the conductive region into a plurality of triangular sections. A mode coupling device, such as a cutout corner of a triangular section, induces orthogonal modes of vibration of an electromagnetic field about the plurality of sections. The ferroelectric oxide is disposed in the slot for adjusting a dielectric constant of the oxide in accordance with a bias voltage applied across the slot between adjacent ones of the sections for turning the patch filter element. Metallic walls may be constructed along edges of the slot for increased capacitance.

Abstract: A flexible waveguide has a flexible wall enclosing an elongated cylindrical passage for transmission of an electromagnetic wave along the passage. A succession of corrugations is disposed along an interior surface of the wall facing the passage. The corrugations are spaced apart by a distance less than approximately 0.2 wavelength of the electromagnetic wave, each of the corrugations having a height greater than the distance but less than approximately 0.5 wavelength of the electromagnetic wave, and each corrugation having a curved surface to minimize loss in the transmission of the electromagnetic wave.

Abstract: A microwave filter cavity that exhibits spurious mode suppression. The microwave filter comprises a metal mode suppression tuning stub located in a replaceable iris plate that is used to suppress unwanted transverse magnetic (TM) modes of the filter cavity, The mode suppression stub is disposed normal to an end wall of the cavity. The mode suppression stub perturbs the E-field of transverse magnetic modes, while having negligible effect on desired transverse electric (TE) modes. The addition of the tuning stub has no effect on filter performance determined by transverse electric modes.

Abstract: A filter includes an electromagnetic wave supporting structure having a cavity defined by an encircling sidewall, and microwave feeds coupled to the cavity for inputting and for outputting electromagnetic power to and from the wave supporting structure. At least a portion of an interior surface of the sidewall has a succession of corrugations. Successive ones of the corrugations are spaced apart by a distance less than approximately 0.2 wavelength of the electromagnetic wave, and each of the corrugations has a height greater than the spacing distance but less than approximately 0.5 wavelength of the electromagnetic wave. The geometry of the corrugated sidewall reduces interaction between the electromagnetic wave and the sidewall to inhibit dissipation of power of the electromagnetic wave within the sidewall.

Abstract: A flexible waveguide has a flexible wall enclosing an elongated cylindrical passage for transmission of an electromagnetic wave along the passage. A succession of corrugations is disposed along an interior surface of the wall facing the passage. The corrugations are spaced apart by a distance less than approximately 0.2 wavelength of the electromagnetic wave, each of the corrugations having a height greater than the distance but less than approximately 0.5 wavelength of the electromagnetic wave, and each corrugation having a curved surface to minimize loss in the transmission of the electromagnetic wave.

Abstract: In a filter assembly having a bandpass filter and a group-delay equalizer coupled thereto by a circulator, there is disposed in the filter and/or the equalizer an electromagnetic wave propagation structure having a cavity with a plurality of tuning elements extending therein. The wave-propagation structure supports a first wave propagating in a first mode and a second wave propagating in a second mode. A first of the tuning elements is positioned to interact with the first wave, a second of the tuning elements is positioned to interact with the second wave, and a third of the tuning elements is positioned for coupling electromagnetic energy between the first wave and the second wave. A fourth of the tuning elements has an orientation perpendicular to an orientation of the third tuning element.

Abstract: A patch filter element has an electrically-insulating substrate with an electrically conductive region on a first surface of said substrate, and a slot such as a crossed slot dividing the conductive region into a plurality of triangular sections. A mode coupling device, such as a cutout corner of a triangular section, induces orthogonal modes of vibration of an electromagnetic field about the plurality of sections. The ferroelectric oxide is disposed in the slot for adjusting a dielectric constant of the oxide in accordance with a bias voltage applied across the slot between adjacent ones of the sections for turning the patch filter element. Metallic walls may be constructed along edges of the slot for increased capacitance.

Abstract: An equalizer that couples a dual-mode dielectric resonator to a planar transmission line, creating an all-pass network. Coupling is achieved using circular polarization of the electromagnetic field in the dielectric resonator. The all-pass, non-reciprocal network is realized by the use of circular polarized energy and an offset cross shaped, through transmission line.

Abstract: An electromagnetic cavity filter is formed by at least two cavities having electrically conductive walls. Each cavity is the equivalent of two filter poles because two orthogonal modes of electromagnetic radiation can resonate within each cavity. Characterizing vector tuning elements are coupled to each of the cavities that are each aligned along respective axes. The tuning elements are used to provoke derivative orthogonal modes and determine the degree of coupling between orthogonal modes. One or more intercavity couplers interconnect the cavities and are rotated at arbitrary angles that are different from the axes of the characterizing vector tuning elements. Electrically adjacent and nonadjacent modes of proximate cavities can be coupled, permitting elliptic filter functions. Electrically nonadjacent modes are coupled by means of an iris interconnecting the two cavities. Electrically adjacent modes are coupled by means of an electrically conductive probe penetrating each of the cavities.

Abstract: An electromagnetic wave propagation structure, suitable for the transmission of an electromagnetic wave and the formation of resonators within filters, is constructed of both high and low dielectric-constant materials wherein the high dielectric-constant is in excess of approximately 80 and the low dielectric-constant is less than approximately 2. A boundary between the high and the low dielectric-constant materials serves as an electric wall to waves propagating in the low dielectric-constant material and as a magnetic wall to waves propagating in the high dielectric-constant material. This permits substitution of the high dielectric-constant material for metal elements, such as resonators and feed structures in filters. Furthermore, the use of a cladding of dielectric material of one of the foregoing dielectric ranges about a core of material of the other of the foregoing dielectric ranges enables construction of waveguides having rectangular and circular cross-sections.

Abstract: A ceramic resonator element having high Q, high dielectric constant, and a low temperature coefficient of resonant frequency is enclosed within a cavity to form a composite microwave resonator having reduced dimensions and weight as compared to a simple cavity resonator. In an exemplary embodiment, a pair of tuning screws extend into the cavity along orthogonal axes to tune the structure to resonance along these axes at frequencies near the fundamental resonance of the ceramic element. Several such cavities can be formed in a short length of waveguide by the use of transverse partitions at spaced intervals and coupling between cavities can be accomplished by using simple slot, cross or circular irises. In each cavity, a mode-perturbing screw is positioned along an axis 45° from each of the orthogonal tuning screws, such that resonance along either of the orthogonal axes is coupled to excite resonance also along the other.

Abstract: An electromagnetic wave propagation structure, suitable for the transmission of an electromagnetic wave and the formation of resonators within filters, is constructed of both high and low dielectric-constant materials wherein the high dielectric-constant is in excess of approximately 80 and the low dielectric-constant is less than approximately 2. A boundary between the high and the low dielectric-constant materials serves as an electric wall to waves propagating in the low dielectric-constant material and as a magnetic wall to waves propagating in the high dielectric-constant material. This permits substitution of the high dielectric-constant material for metal elements, such as resonators and feed structures in filters. Furthermore, the use of a cladding of dielectric material of one of the foregoing dielectric ranges about a core of material of the other of the foregoing dielectric ranges enables construction of waveguides having rectangular and circular cross-sections.