Abstract:
For wireless cellular communications, a "smart" multi-band combiner system has a multi-band combiner and a passive inter-modulation (PIM) detection sub-system. The multi-band combiner combines multiple transmit signals in different downlink frequency bands into a single, multi-band transmit signal for transmission from a cell tower antenna. The PIM detection sub-system characterizes the frequency components in the multi-band transmit signal to predict PIM products and determine if any predicted PIM products might interfere with any receive signals in any uplink frequency bands. If so, the PIM detection sub-system generates a signal indicating the presence of such predicted interfering PIM products, and the system installer and/or the network administrator can take remedial action to prevent the PIM products from interfering with user communications.
Abstract:
A metallized dielectric waveguide filter includes an upper metallized dielectric waveguide having a plurality of upper resonant cavities, the upper metallized dielectric waveguide comprising an upper dielectric block having metallized outer walls, and a lower metallized dielectric waveguide having a plurality of lower resonant cavities, the lower metallized dielectric waveguide comprising a lower dielectric block having metallized outer walls. A first of the upper resonant cavities is operatively connected to a first of the lower resonant cavities via at least one coupling window. A first slot having metallized walls is provided in a portion of the upper dielectric block that is part of the first of the upper resonant cavities.
Abstract:
A resonant cavity filter has a housing having a resonator mounted therein, a tuning screw that comprises a head portion, a metallic tuning element and a dielectric spacer interposed between the head portion and the metallic tuning element. The tuning screw is mounted for coaxial insertion into an interior of the resonator to adjust a frequency response of the resonant cavity filter.
Abstract:
A bandpass filter has a combline structure having a plurality of cascaded nodes (503, 504, 506, 508 ). A plurality of nodes in the filter are connected both to resonant elements ( 514, 517 ) (a.k.a. resonators) and non-resonant elements ( 601, 604 ) (including elements having inductances and/or capacitances that do not resonate in a predetermined frequency band of interest). The resonant frequencies of the resonant elements may be adjusted, in order to adjust the location of the center frequency and/or the width of the passband of the filter. The characteristics of the resonant and non-resonant elements are selected such that the poles of the filter, when plotted on the complex plane, move substantially along the imaginary axis when the resonant frequencies are adjusted, without substantial movement along the real axis. The resulting bandpass filter has substantially constant losses and substantially constant absolute selectivity over a relatively wide range of bandwidths.
Abstract:
TX/RX switch circuits include an input, a first circulator having a first port coupled to the input, a circuit element having a first port coupled to a second port of the first circulator, a second circulator having a first port coupled to a second port of the circuit element, an output coupled to a second port of the second circulator, a low noise amplifier coupled between a third port of the second circulator and a third port of the first circulator, a bias circuit that is configured to set an impedance at a third port of the circuit element at a first impedance level when operating in transmit mode and to set the impedance at the third port of the circuit element to have a second impedance level when operating in receive mode, and a first PIN diode coupled between an output of the low noise amplifier and electrical ground.
Abstract:
A suspended microstrip filtering device comprises a printed circuit board that includes a substrate having at least one resonator thereon, a ground plate, and an insulating separator interposed between the printed circuit board and the ground plate, the insulating separator having a plurality of air-filled openings.
Abstract:
Bias tees are provided that include a radio frequency (RF) transmission line. The bias tees include a dielectric material that is configured to provide a capacitance between the RF transmission line and ground. The bias tees include a high-frequency port, a common port,and a low-frequency port, and the RF transmission line is coupled between the common port and the low-frequency port.
Abstract:
The present invention provides target devices such as filter units with at least one receiving channel with a stop surface that is electrically conductive and at least one cable with a connector assembly on a first end portion. The connector assembly includes a first member with an open channel. The first member is coupled to the end portion of the outer conductor with the free end of the inner conductor and the end portion of the dielectric extending through the open channel to reside forward of the first member. The first member resides in a respective one of the at least one receiving channel against the stop surface. The connector assembly also includes a second member with an open channel. The second member is slidably coupled to the first end portion of the at least one cable and presses the first member against the stop surface.
Abstract:
Filter devices are provided herein. In some embodiments, a filter device includes first and second resonator stalks in respective first and second openings in a PCB that has first and second metal resonator heads that are on the first and second resonator stalks, respectively. Moreover, in some embodiments, a filter device includes a metal resonator head that has a loop portion on a resonator stalk and a plurality of arms that extend outward from the loop portion.
Abstract:
A resonant cavity filter includes a filter housing defining an internal cavity therein, a resonating element in the internal cavity of the filter housing, and a coupling transmission line extending adjacent a periphery of the resonating element in the internal cavity of the filter housing. The resonating element is rotatable relative to the coupling transmission line to vary an electromagnetic coupling therebetween. Related devices and methods of operation are also discussed.