Abstract: Waveguide phase shifter (200, FIG. 2 and 300, FIG. 3) uses piezoelectric ceramics to implement a voltage variable actuator (270, 370) for moving at least one dielectric vane (255, 355) relative to a reference surface (206, 306) in a waveguide cavity (285, 385). In this manner, the phase shift in waveguide phase shifters (200, 300) is controlled. In one embodiment, actuator (270) comprises first piezoelectric wafer (210), second piezoelectric wafer (220), first metallic layer (230), second metallic layer (240), third metallic layer (250), mating surface (272) and spacer (265). Actuator (270) uses a stack of piezoelectric materials to establish a lever arm mechanism to establish vertical movement (294) and move dielectric vane (255). Actuator (370) uses a stack of piezoelectric materials to establish vertical movement (394) and move dielectric vane (355). Waveguide phase shifters (200, 300) are used in phased array antenna (400) operating at microwave frequencies.

Abstract: A phased array antenna (1000) is formed using a number of independently controllable piezoelectric phase shifters (1300) which results in a low cost phased array antenna that is functional at microwave and/or millimeter wave frequencies. In addition, the independently controllable piezoelectric phase shifters (1300) have sufficient phase range to allow a single antenna to be steered over a wide angle field of view. Piezoelectric phase shifters (1300) comprise at least one-voltage variable capacitor (1310, 1320, FIG. 2). Typically, the piezoelectric material used in the voltage variable capacitors is selected from a group consisting of lead-titanate (PbTiO.sub.3), lead-zirconate (PbZrO.sub.3), barium-titanate (BaTiO.sub.3), and lead-zirconate-titanate (PbZr.sub.x Ti.sub.1-x O.sub.3), where x varies from zero to one.

Abstract: An acoustic wave ladder filter (30) with lossy inductances (42) connected in parallel with resonators (40). Shunt sections (36,37) of the ladder filter (30) include impedance inverters having pass frequencies within the stopband of series resonators (33,34,35). The filter (30) additionally includes variable capacitors (44) connected in parallel with the inductances (42) to provide adjustment capabilities. The use of lossy inductances (42) actually increases effective coupling coefficient of the filter (30) and improves insertion loss thereby allowing improved design flexibility.

Abstract: A low loss high frequency transmitting/receiving switching module (100) having an input and output port (106,110), that individually may be connected to an antenna or external port (108,112) by applying an appropriate bias potential to a switching circuit (140). The switching circuit (140) is designed to operate with only a single diode (130). This is accomplished by using two, four-port 3 db directional couplers (102,104) connected with two coupling lines (114,118). The switching diode (130) is used to add or delete a transmission line (142) in one of the coupling lines (118) to proved a signal phase shift. The switching circuit (140) switches in or out a 180 degree phase shift to change the phase relationship between signals in the two sets of coupling lines (114,116,118,120) to determine which ports (106,108,110,112) of the directional couplers (102,104) are interconnected.

Abstract: A high Q multi-layer ceramic transmission line resonator (100) used for RF applications. The resonator (100) includes a plurality of strips (102) which are separated by a ceramic substrate (104). Each of the strips are interconnected using vias (110) passing through the ceramic substrate (104). The invention utilizes current manufacturing processes to fabricate an equivalent thick center conductor to effectively increase the Q factor. This allows for the resonator to be used in miniature RF communication devices utilized in high tier devices such as voltage controlled oscillators (VCOs) or integrated filter circuits.

Abstract: What is described is a commonly coupled high frequency transmitting/receiving switching module (100). The switching module (100), has a transmitting circuit (102), a receiving circuit (104), an antenna circuit (106), an external circuit (108), a coupling circuit (110) and control circuits (124, 126). The switching module may be switched between one of four circuit paths (202, 204, 206, 208) each path incorporating an integral harmonic filter (210, 212). This structure is adapted for use in a multi-layer ceramic integrated circuit, and provides the advantage of minimizing current consumption with a minimal number of components.

Abstract: A switch circuit for a cellular radiotelephone operable in a TDMA communication scheme. The switch circuit is disposed upon a plurality of tandemly-positioned ceramic substrates having transmission lines disposed upon one of the ceramic substrates. The switch circuit alternately connects transmitter circuitry to an antenna or receiver circuitry to the antenna, thereby alternately to permit transmission or reception of signals generated by, or received by the radiotelephone. Because circuits disposed upon ceramic materials are of low insertion losses, the switch circuit is advantageously utilized to form a portion of the radiotelephone.

Abstract: A transmission line device (200) employs a first ground plane (118) that is disposed on a first dielectric substrate (202). A first conductive layer (210) that encloses a first area (213)is disposed on a second dielectric substrate (206), which substrate is positioned substantially adjacent to the first dielectric substrate (202). A second conductive layer (211) that encloses an area corresponding to the first area (213) is disposed on a third dielectric substrate (207), which substrate is positioned substantially adjacent to the second dielectric substrate (206). A coil structure is thereby provided that can be employed in the fabrication of a transmission line device, according to the invention.

Abstract: An electrical circuit (500) includes an input means (503) for providing an input signal, an output means for providing an output signal, and a transmission line device (421) disposed substantially between the input means (503) and the output means. The transmission line device inludes a first ground plane (505) disposed on a first dielectric substrate (502), and a first conductive layer (421-1) disposed, and enclosing a first area, on a second dielectric substrate (506) that is positioned substantially adjacent to the first dielectric substrate (502). The transmission line device (421) further includes a second conductive layer (421-2) that encloses an area corresponding to the first area on a first major surface of a third dielectric substrate (504) that is positioned substantially adjacent to the second dielectric substrate (506).

Abstract: A pseudo rod, fabricated from several plate sections joined together at their edges and having a cross-section resembling a polygon approximates a rod having a circular cross section. Using multiple plates joined at their edges permits growing a crystalline material on the planar faced substrates and if the plates are crystalline material, the crystalline material grown thereon can have improved current carrying capability.

Abstract: A single-block ceramic filter (102) is coupled to two antennas (142 and 144) for providing both antenna duplexing and antenna-switched diversity in a duplex radio transceiver (100). One antenna (142) is coupled by the filter (102) to a transmitter (132), and both antennas (142 and 144) are switchably coupled by the filter (102) to a receiver (130) by diversity control circuitry (101) in response to a diversity control signal (137). A microcomputer (134) in the transceiver (100) is coupled to the receiver (130) for monitoring the received signal strength (135). When the received signal strength (135) drops in level indicating that the signal being received on one of the antennas (142 or 144) has become degraded due to fading or other interference, the microcomputer (134) changes the binary state of the diversity control signal (137) for switching the receiver (130) to the other one of the antennas (142 or 144 ).

Abstract: A single-block ceramic filter (102) is coupled to two antennas (142 and 144) for providing both antenna duplexing and antenna-summed diversity in a duplex radio transceiver (100). One antenna (142) is coupled by the filter (102) to a transmitter (132) and to a receiver (130), and a second antenna (144) is switchably coupled by the filter (102) to the receiver (130) by diversity control circuitry (101) in response to a diversity control signal (137). A microcomputer (134) in the transceiver (100) is coupled to the receiver (130) for monitoring the received signal strength (135). When the received signal strength (135) drops in level indicating that the signal being received on the antennas (142 to 144) has become degraded due to fading or other interference, the microcomputer (134) changes the binary state of the diversity control signal (137) for switching the receiver (130) between antenna (142) and both antennas (142 and 144).

Abstract: A microwave cavity filter using resonators of superconducting coatings, one-half wavelength long on quartz tubes mounted within the cavity that carry refrigerant to cool the superconductor substantially reduces ohmic losses and permits shrinking the size of conventional cavity filters.

Abstract: A ceramic filter employs a novel tuning process which avoids the necessity of etching or abrading plating on the surface of the filter. The tuning is provided by determining a selected frequency related characteristic of the dielectric making up the block portion of the ceramic filter. For example, the quarter wave length frequency of the block may be measured. Next, plating artwork is designed in accordance with the determined selected frequency related characteristic. The artwork is then used for selectively applying a conductive material to a surface of the block in order to shift the determined selected frequency related characteristic to a desired (specified) frequency characteristic. By appropriately designing the artwork based on the determined selected frequency related characteristic, no etching or abrading to the plating on the block is required.

Abstract: A single-block ceramic filter (100) providing both pass and stop bands couples an RF signal from transmitter (180) to an antenna (190) and an RF signal from the antenna (190) to a receiver (170). The ceramic filter (100) includes seven holes (102, 104, 106, 108, 110, 112 and 114) each having an elongated cross section and being surrounded by capacitive strips (e.g. 130, 131, 140 and 141 for hole 106), and electrodes (120, 122 and 124) coupled to receiver (170), transmitter (180) and antenna (190), respectively. A bracket (150) may be soldered to the ceramic filter (100) for holding cables coupled to the receiver, transmitter and antenna and for mounting the ceramic filter in a radio transceiver.

Abstract: An RF filter (100) includes a ceramic resonator (116) sandwiched between first and second compensating discs (114 and 120) for temperature compensation, low loss mounting and heat sinking of the ceramic resonator (116). Good thermal contact between the ceramic resonator (116) and discs (114 and 120) is produced by a compressive force applied by copper plates (112 and 128) and copper can (124). The resonant frequency of the RF filter is tuned by means of a copper-plated tuning shaft (104) and ceramic tuning slug (118) which are positioned by brass bushing (134) in copper pipe (130 and 132). Input and output signals are coupled to the RF filter via respective probes (122).

Abstract: This invention is directed to a same frequency repeater (SFR) for use in a multiple SFR system in which only one SFR at a given time is allowed to retransmit a received signal thereby preventing simulcast distortion which could occur due to multiple SFR retransmissions. The SFR includes a receiver for receiving a signal carrying information at a given frequency and a transmitter for rebroadcasting the received signal at the given frequency. A mechanism is provided for keying the transmitter upon the reception of a received signal. A detector senses if a predetermined pilot tone is carried by the received signal. A mechanism responsive to the detection of the pilot tone inhibits the keying of the transmitter if the pilot tone is detected before the transmitter is keyed. A tone generator encodes the output signal of the transmitter with the pilot tone.

Abstract: An absorptive resonant cavity filter suitable for use on the output of a transmitter power amplifier and capable of substantially constant predetermined resistive input impedance at all frequencies. The structure comprises a bandpass cavity which instead of an input coupling loop employs a conductor coupled from the input and configured along the wall of the cavity to form a transmission line of predetermined impedance and terminated by a resistor of similar impedance value.

Abstract: An apparatus for minimizing the spillover signal from the transmitter to the receiver in a same frequency repeater includes a mechanism for generating a receiver first injection signal carrying the modulation component of the transmitter signal, and a first mixer for mixing the received signals and the first injection signal to produce a first IF signal having one unmodulated IF component signal and another modulated IF component signal. A correlation and cancellation circuit is utilized to cancel the unmodulated IF component signal. A mechanism is provided for generating a second injection signal which carries the modulation component of the transmitter signal. A second mixer mixes the first IF signal and the second injection signal to produce a second IF signal such that the modulation component of the spillover signal is substantially cancelled.

Abstract: The inventive lens focuses a plurality of radio frequency signals received by a multi-element antenna array into a coherent signal.A circular transmission cavity has probe sites located therein. The probe sites are located on radii of the circular cavity approximately one quarter wavelength of the radio frequency of interest from the cavity's perimeter. A probe pair is positioned at each probe site. The signal from each antenna element is coupled through a three port circulator to a particular probe pair via a 180.degree. coupler. Incoherent images received at the probe pair are dumped in a load resistor, whereas the focused image of the received signal is routed through the circulator and to a receiver.