Abstract: A thin film resonator and method includes a first electrode (110) and a second electrode (112) substantially parallel to the first electrode (110). An intermediate layer (120) is disposed between and coupled to the first and second electrode (110, 112). The intermediate layer (120) includes a first piezoelectric layer (122), a second piezoelectric layer (124), and a spacer layer (130) disposed between the first and second piezoelectric layers (122, 124). The spacer layer (130) has an acoustic impedance substantially the same as the first and second piezoelectric layers (122, 124) and is formed of a disparate material.

Abstract: A concentrator (11) coupled to a wired network (13) also acts as a master device relative to each of a plurality of ad hoc wireless communication networks (15), thereby permitting wireless communication devices in the ad hoc networks to access the wired network. The concentrator utilizes antenna array processing and beamforming techniques when communicating with the devices of the various networks, in order to advantageously reduce communication interference between the networks.

Abstract: A concentrator (11) coupled to a wired network (13) also acts as a master device relative to each of a plurality of ad hoc wireless communication networks (15), thereby permitting wireless communication devices in the ad hoc networks to access the wired network. The concentrator utilizes antenna array processing and beamforming techniques when communicating with the devices of the various networks, in order to advantageously reduce communication interference between the networks.

Abstract: A system and method for wireless communication between two devices allows the transfer of location information through a cellular or “BLUETOOTH” link that can be used to provide a continuous indication of estimated distance and direction relative to the two devices in communication with one another.

Abstract: A network of electronic devices such as computers (50) and/or calculators (36, 38) uses low power communication to transmit wireless signals through a distributed antenna system (40). The distributed antenna system may be formed in conjunction with ceiling or floor tiles 62 or modular office components (44 and 46) or student desks. The distributed antenna system 40 reduces the effective distance between a transmitting and receiving device to a nominal distance.

Abstract: An acoustic reflector (48) is applied over a thin-film piezoelectric resonator (41, 61) which is supported on a semiconductor or semiconductor-compatible substrate (42, 62) of a microelectronic device (40, 60), enabling an encapsulant (49) to be applied over the reflector-covered resonator without acoustically damping the resonator. In one embodiment, alternating high and low acoustic impedance layers (51, 53 . . . 55) of one-quarter wavelength thicknesses constructively reflect the resonating wavelength to make an encapsulant in the form of an inexpensive plastic molding compound appear as a "clamping" surface to a resonator (41) peripherally supported over an opening (43) on a silicon substrate (42). In another embodiment, an encapsulant- and reflector-covered resonator (61) is mechanically supported above a second reflector (68) which eliminates the need for peripheral support, making substrate (68) also appear as a clamping surface.

Abstract: A network/portable computer (18) includes a modular bay (20) which can receive either a hard drive (22) or a data transceiver (24) for establishing a wireless network connection. When the network/portable computer (18) is in the local area covered by the network (10), the data transceiver (24) is installed to use the network (10) for storage and retrieval of data. When used in a remote area, where a network connection cannot be established, the hard drive (22) is installed in the modular bay (20) to provide a full featured computer.

Abstract: A network (10) of mobile computing devices (18) communicates by receiving and rebroadcasting messages using wireless transmission. A message is initiated by first mobile computing device and transmitted to a set of other mobile computing devices which may be selected on an ad hoc basis. The receiving mobile computing devices rebroadcast the message to other of the mobile computing devices (18) which have not received the message. The message is repeatedly rebroadcast until all mobile computing devices (18) have received the message or, if the message is intended for particular selected mobile computing devices (18), until all selected devices have received the message.

Abstract: A digitally controlled programmable transversal filter (DCPTF) employing a lithium niobate surface acoustic wave (SAW) delay line and two large scale integration (LSI) gallium arsenide integrated circuits to digitally control the magnitude and sign of the 32 tap weights from the delay line. The DCPTF results in a significant reduction in size over the prior art with little sacrifice in performance. The DCPTF is completely programmable and is constrained only by the bandwidth and the number of taps.

Abstract: A method of adjusting the center frequency of a SAW device by providing a substrate capable of propagating a surface acoustic wave thereon having input transducer electrode on one end portion thereof, output transducer electrodes on the opposite end portion thereof and a waveguide portion therebetween, applying an RF input signal to the input transducer and providing an indication of the output obtained from the output transducer and etching the entire device with an etchant until the indication has reached a predetermined status.

Abstract: A hybrid programmable transversal filter (HPTF) is described that employs a LiNbO.sub.3 SAW delay line and two monolithic dual-gate GaAs FET arrays to control magnitude and sign of the 16 tap weights. The HPTF is completely programmable and is constrained only by the bandwidth (100 MHz centered at 250 MHz) and the number of taps. Theoretical calculations of tap weight control range and dynamic range are presented, compared with experiment and used to justify the hybrid LiNbO.sub.3 SAW - GaAs FET combination. Dynamic range of 85 dB and a continuously variable tap weight control range of 70 dB are demonstrated.