Abstract: In a multiple-carrier modulation system, each carrier signal of the multiple carrier system is distributed, recombined, optionally band pass filtered, and transmitted to downlink devices such as cellular phones. The distribution and recombination is performed by either a space-fed technique or through the use of a Rotman lens fed in reverse. The phases of the distributed signals are controlled to be coherent when recombined. Also, a capacity of the multiple carrier system is enhanced through polarization of the carriers in a space-fed version of the system.

Abstract: A phase shifter including a phase-shifting slab having a phase-shifting member is used in conjunction with a quasi-TEM transmission line having at least one active line and one ground. In some embodiments, the phase-shifting slab is inserted between the active line and the ground. The phase-shifting member is advantageously configured so that as it is advanced between the active line and the ground plane, a varying amount of dielectric material passes therebetween. Varying the amount of dielectric material between the active line and the ground changes the effective dielectric constant of the transmission line. Such a change in the effective dielectric constant causes a change in the propagation velocity of a signal traveling through the transmission line. In that manner, a phase shift is introduced in the signal relative to other signals.

Abstract: A phased-array antenna in accordance with illustrative embodiments of the present invention advantageously includes a plurality of radiating elements and a phase-shifter array integrated into a feed line of the antenna's series feed network. The phase-shifter array advantageously comprises a plurality of phase-shifting slabs each of which includes a phase-shifting member, advantageously comprised of a dielectric material. When placed in electromagnetic fields generated by signals propagating through different regions of a feed line, the phase-shifting members affect the phase of such signals. Each slab in the phase-shifter array also advantageously incorporates at least one impedance-matching member that decreases or eliminates an impedance mismatch between air-suspended and dielectric-loaded regions of the transmission line over the full phase-shifting range of the phase-shifting members.

Abstract: A phased-array antenna having either a corporate or series feed network advantageously includes a phase-shifter array comprised of mechanical phase shifters for beam steering. In some embodiments, the phase-shifter array includes a plurality of phase-shifting slabs each of which includes a phase-shifting member advantageously comprised of a dielectric material. When placed in electromagnetic fields generated by signals propagating through different regions of a transmission line, the phase-shifting members affect the phase of such signals. In some embodiments, the plurality of phase-shifting slabs are mechanically linked by a rigid linkage that is driven by a single driving mechanism. In those embodiments, the phase-shifting slabs and incorporated phase-shifting members in the phase-shifter array are moved in unison, relative to the transmission line, causing a shift in the relative phases of a multiplicity of signals, thereby steering the antenna beam.

Abstract: A vehicle alarm for preventing injury to persons near the vehicle. Persons under and around a vehicle such as a school bus are detected by establishing an energy field and monitoring for disturbances therein. At least one transmitter establishes the energy field in areas of high risk. One or more receivers detect a signal resulting from the energy field. These signals are monitored by a processor unit for amplitude variations therein. The processor unit preferably stores the amplitude of the received signal when no persons are present and establishes one or more thresholds preferably in accordance with the stored amplitude. The received signal is subsequently monitored for variations that result in a threshold crossing indicating the unwanted presence of a person in a danger zone. When a threshold crossing is detected an alarm is activated.