Abstract: Embodiments disclosed herein relate to programmable duplexers. The frequency pass band of the programmable duplexer is changed according to a selection of a channel-pair to control or maximize the transition band between the receiver path and the transmitter path. The programmable duplexer permits selections of desired pass bands without the need for multiple duplexer filters. Embodiments disclosed herein also relate to temperature compensating a programmable duplexer based upon one or more temperature indications. The one or more temperature indications may be based upon a temperature of a semiconductor circuit, a temperature of a substrate of a one-port resonator of the programmable duplexer, and/or a temperature of the one-port resonator. The resulting programmable duplexer has an added additional advantage of lessening the temperature variations of the programmable duplexer.

Abstract: A radio frequency (RF) switch adapted to reduce third order intermodulation (IM3) products generated as RF signals propagate through the RF switch is disclosed. The RF switch includes N semiconductor switch segments, and N?1 phase shift networks, individual ones of the N?1 phase shift networks being coupled between adjacent ones of the N semiconductor switch segments where N is a natural number greater than 1. In operation, when the RF switch is on, IM3 products generated by the RF switch propagating through the N?1 phase shift networks are phase shifted such that the IM3 products are at least partially canceled.

Abstract: An RF system for suppressing third-order intermodulation (IM3) products is disclosed. The RF system is made up of a plurality of branches coupled in parallel. Each of the plurality of branches includes a positive phase shift network, a negative phase shift network, and nonlinear components, wherein the nonlinear components are coupled between the positive phase shift network and the negative phase shift network. The RF system also includes a null offset branch with nonlinear components that are coupled in parallel with the plurality of branches. In one embodiment, the nonlinear components are series stacked field effect transistors (FETs) that comprise an RF switch having a switch segment for the null offset branch and a switch segment for each of the plurality of branches. The RF switch further includes a control terminal for turning the FETs on and off.

Abstract: Embodiments disclosed herein relate to programmable duplexers. The frequency pass band of the programmable duplexer is changed according to a selection of a channel-pair selection to control or maximize the transition band between the receiver path and the transmitter path. The programmable duplexer permits selections of desired pass bands without the need for multiple duplexer filters. As an additional advantage, the transmission band requirements become less sensitive to manufacturing tolerances and temperature variations.

Abstract: Disclosed is a diplexed transmit (TX) filter and RF switch for suppressing third order intermodulation (IM3) products. Included are first and second duplexers each having a receive (RX) port, a TX port, and an RX/TX port. Also included are first and second power splitter/combiners each having first, second, and third terminals. Further included are first, second, and third phase shift networks. The first power splitter/combiner's first terminal is coupled to the first duplexer's TX port and a first switch segment is coupled between the first duplexer's RX/TX port and the first terminal of the second coupler. The first phase shift network is coupled to the second duplexer's TX port and a second switch segment in series with the second phase shift network is coupled between the second duplexer's RX/TX port and second coupler's second terminal. The third phase shift network is coupled to the second duplexer's RX terminal.

Abstract: An RF system for reducing intermodulation (IM) products is disclosed. The RF system includes a first nonlinear element and a second nonlinear element, wherein the second nonlinear element generates inherent IM products and the first nonlinear element is adapted to generate compensating IM products. Alternatively, the first nonlinear element generates inherent IM products and the second nonlinear element is adapted to generate compensating IM products. The amplitudes of the compensating IM products are substantially equal to amplitudes of the inherent IM products. The RF system further includes a phase shifter that is adapted to provide a phase shift that results in around 180° of phase shift between the inherent IM products and the compensating IM products. The phase shifter is coupled between the first nonlinear element and the second nonlinear element.

Abstract: The present disclosure relates to a passive multi-band duplexer having a first bandpass filter and a second bandpass filter. The first bandpass filter includes a first group of sub-band bandpass filters, a first switching circuit, and a first tunable LC bandpass filter. Similarly, the second bandpass filter includes a second group of sub-band bandpass filters, a second switching circuit, and a second tunable LC bandpass filter. A first band of the passive multi-band duplexer, such as a transmit band, is chosen by selecting one of the first group of sub-band bandpass filters and tuning the first tunable LC bandpass filter to the first band. Similarly, a second band of the passive multi-band duplexer, such as a receive band, is chosen by selecting one of the second group of sub-band bandpass filters and tuning the second tunable LC bandpass filter to the second band.

Abstract: Embodiments disclosed herein relate to programmable duplexers. The frequency pass band of the programmable duplexer is changed according to a selection of a channel-pair to control or maximize the transition band between the receiver path and the transmitter path. The programmable duplexer permits selections of desired pass bands without the need for multiple duplexer filters. Embodiments disclosed herein also relate to temperature compensating a programmable duplexer based upon one or more temperature indications. The one or more temperature indications may be based upon a temperature of a semiconductor circuit, a temperature of a substrate of a one-port resonator of the programmable duplexer, and/or a temperature of the one-port resonator. The resulting programmable duplexer has an added additional advantage of lessening the temperature variations of the programmable duplexer.

Abstract: An RF system for reducing intermodulation (IM) products is disclosed. The RF system includes a first nonlinear element and a second nonlinear element, wherein the second nonlinear element generates inherent IM products and the first nonlinear element is adapted to generate compensating IM products. Alternatively, the first nonlinear element generates inherent IM products and the second nonlinear element is adapted to generate compensating IM products. The amplitudes of the compensating IM products are substantially equal to amplitudes of the inherent IM products. The RF system further includes a phase shifter that is adapted to provide a phase shift that results in around 180° of phase shift between the inherent IM products and the compensating IM products. The phase shifter is coupled between the first nonlinear element and the second nonlinear element.

Abstract: An RF system for suppressing third-order intermodulation (IM3) products is disclosed. The RF system is made up of a plurality of branches coupled in parallel. Each of the plurality of branches includes a positive phase shift network, a negative phase shift network, and nonlinear components, wherein the nonlinear components are coupled between the positive phase shift network and the negative phase shift network. The RF system also includes a null offset branch with nonlinear components that are coupled in parallel with the plurality of branches. In one embodiment, the nonlinear components are series stacked field effect transistors (FETs) that comprise an RF switch having a switch segment for the null offset branch and a switch segment for each of the plurality of branches. The RF switch further includes a control terminal for turning the FETs on and off.

Abstract: Disclosed is a diplexed transmit (TX) filter and RF switch for suppressing third order intermodulation (IM3) products. Included are first and second duplexers each having a receive (RX) port, a TX port, and an RX/TX port. Also included are first and second power splitter/combiners each having first, second, and third terminals. Further included are first, second, and third phase shift networks. The first power splitter/combiner's first terminal is coupled to the first duplexer's TX port and a first switch segment is coupled between the first duplexer's RX/TX port and the first terminal of the second coupler. The first phase shift network is coupled to the second duplexer's TX port and a second switch segment in series with the second phase shift network is coupled between the second duplexer's RX/TX port and second coupler's second terminal. The third phase shift network is coupled to the second duplexer's RX terminal.

Abstract: A radio frequency (RF) switch adapted to reduce third order intermodulation (IM3) products generated as RF signals propagate through the RF switch is disclosed. The RF switch includes N semiconductor switch segments, and N?1 phase shift networks, individual ones of the N?1 phase shift networks being coupled between adjacent ones of the N semiconductor switch segments where N is a natural number greater than 1. In operation, when the RF switch is on, IM3 products generated by the RF switch propagating through the N?1 phase shift networks are phase shifted such that the IM3 products are at least partially canceled.

Abstract: Embodiments disclosed herein relate to programmable duplexers. The frequency pass band of the programmable duplexer is changed according to a selection of a channel-pair selection to control or maximize the transition band between the receiver path and the transmitter path. The programmable duplexer permits selections of desired pass bands without the need for multiple duplexer filters. As an additional advantage, the transmission band requirements become less sensitive to manufacturing tolerances and temperature variations.

Abstract: The present invention is a split band duplexer, which increases the separation between a transmit passband and a receive passband by splitting the transmit and receive passbands into sub-bands. Each sub-band has a bandwidth that is less than the bandwidth of the full passband. The increased separation increases isolation margins and insertion loss margins, which allows use of standard filter components, such as surface acoustic wave (SAW) filters, and their accompanying manufacturing tolerances and drift characteristics. In one embodiment of the present invention, the split band duplexer includes a first sub-band duplexer and a second sub-band duplexer. The first sub-band duplexer may provide a full bandwidth transmit passband and a receive passband that is less than full bandwidth. The second sub-band duplexer may provide a full bandwidth receive passband and a transmit passband that is less than full bandwidth.

Abstract: A SAW ladder filter includes grating pads extending from opposing bus bars and interdigital transducer electrodes extending from the grating pads for defining an acoustic aperture. The metalization ratio for the grating pads is greater than that for the interdigital transducer electrodes. Reflector electrodes are disposed on opposing longitudinal sides of the interdigital transducer electrodes. Operation of the filter results in a velocity of the SAW along the grating pads slower than a SAW velocity along the plurality of interdigital transducer electrodes, thus producing a wave guiding effect for optimizing SAW propagation within the acoustic aperture. The grating pads may be longitudinally offset from cooperating interdigital transducer electrodes using minor bus bars.

Abstract: A longitudinally coupled leaky surface acoustic wave (LSAW) resonator filter has a wide bandwidth, low insertion loss and return loss characteristics, and high power handling capability. The LSAW resonator filter includes a plurality of longitudinally coupled LSAW resonator tracks disposed upon a piezoelectric substrate and connected in series. The resonator tracks each include reflective gratings and interdigital transducers (IDTs) disposed end-to-end. Acoustic resonant cavities are formed between each IDT and its neighboring IDTs or gratings by chirping the fingers of the IDT in the vicinity of the cavities. Phase discontinuity is eliminated; reflective bulk acoustic wave scattering is reduced; and improved insertion loss and power handling capability are achieved.

Abstract: A hybrid leaky surface acoustic wave (LSAW) resonator filter has a wide bandwidth, low insertion loss and return loss, and excellent rejection of frequencies outside the passband, and includes one or more longitudinally coupled LSAW resonator filter tracks with chirp-type resonant cavities, reflective gratings, and a plurality of interdigital transducers (IDTs) disposed end-to-end therebetween. An acoustic resonant cavity is formed between each of the IDTs and its neighboring IDTs or gratings by chirping the fingers of the IDTs in the vicinity of the cavity. A one or more LSAW impedance element filters are disposed upon the same substrate and connected in series and/or shunt with the longitudinally coupled LSAW resonator tracks. The frequencies of the LSAW impedance-element filters are chosen such that their combination with the longitudinally coupled LSAW resonator filter tracks results in the formation of deep nulls in the overall transfer function at frequencies just outside of the passband.

Abstract: A method and apparatus for improving temperature stability of surface-launched acoustic wave sensors is described. The system includes a plurality of acoustic wave delay lines or resonators coated with identical films which are physically, chemically, biologically, or otherwise sensitive to one or more target chemical or biological analytes. At least one of the delay lines or resonators, referred to herein as reference channels, is used as a frequency reference to which the oscillation frequencies of the remainder of the delay lines or resonators, referred to as sensing channels, are compared. A thin coating of material that is preferably a passivation layer not sensitive to the analytes, is disposed upon the surface-launched acoustic wave sensor. The passivation layer covers sensing films on the reference channels, blocking or impeding interaction of the sensing films and the analytes thereby.

Abstract: An apparatus for reading radially patterned magnetic data from circular objects, such as tokens used by the gaming, transportation, entertainment and other industries. A method of reading the data from such a token.

Abstract: A surface acoustic wave (SAW) sensor system and associated method for accurately measuring mercury gas concentrations. The sensor includes a SAW device that may be a SAW delay-line oscillator or a SAW resonator. The surface of the piezoelectric substrate of the SAW device includes a material suitable for amalgamation with mercury. Mercury in the gaseous environment is captured with the amalgamating material so as to cause a change in the mechanical and electrical properties on the surface of the device, thereby causing a change in the frequency output of the device. The piezoelectric substrate of the SAW device is preferably coupled to a heater to permit control of the temperature at the surface of the device. The piezoelectric substrate temperature may be regulated to produce a substantial equilibrium of mercury amalgamation/desorption kinetics. Under the conditions provided by the invention, the mercury concentration in the gaseous environment can be determined.