Abstract: A resonator is provided with a tuning element based on piezoelectricity. The piezoelectric basic element includes at least one piezoelectric layer and a metal layer. Such a basic element is first coated with a thin insulating layer and then with a good conductor. The thickness of the conductive coating is greater than the skin depth of a field corresponding to the operating frequency of the structure in the conductor. The tuning element formed in this manner is fastened on, e.g., some inner surface of the resonator cavity and acts to change the natural frequency of the resonator by electric control. When using the tuning element, no mechanical arrangement is required for moving the tuning element. Furthermore, the tuning element does not cause considerable dielectric losses nor intermodulation when being in a radiofrequency electromagnetic field, because the field cannot significantly penetrate through said conductive coating into the piezoelectric material.

Abstract: An amplifier unit to be placed in an antenna mast and belonging to a two-way radio system. The amplifier unit comprises two front stages for implementing diversity, each front stage comprising a receiving branch with an amplifier and a transmitting branch including a transmit bandpass filter. In both front stages the output of the receiving branch and the input of the transmitting branch are coupled together and further to a base station (BT1, BT2) by an intermediate cable. There is at least one pair of antenna radiators. One radiator of the pair is coupled to the input of the receiving branch of the first front stage and the output of the transmitting branch of the second front stage, and the other radiator to the input of the receiving branch of the second front stage and the output of the transmitting branch of the first front stage. Then, the feedback path of the signal amplified in the receiving branch circulates for the part of both front stages via both radiators and the airspace.

Abstract: There is disclosed an electromagnetic transmission line arrangement with a phase shifter, comprising at least one conductive branch line (51a,51b) extending from a junction point (51c) to an associated output port, for the propagation of electromagnetic signals in a frequency band along said branch line. The phase shifter includes at least one dielectric body (52,53,54) which is mounted so as to be movable sideways in a transverse direction into a delaying position at least partly covering said branch line (51a,51b). The longitudinal distribution of its dielectric material (?) is adapted to cause, when being moved transversally into said delay position, a controlled phase shift but also to secure, by way of said selected longitudinal distribution of its dielectric material in conjunction with said at least one branch line, an input impedance matching of said transmission line arrangement. The transmission line arrangement can be used in the feeding network to a microwave antenna.

Abstract: The invention relates to an arrangement for bypassing a low noise amplifier unit in the front stage of a radio receiver, especially intended for the base stations of mobile communication networks. The front stage includes, in succession, a divider (420), an amplifier unit (430) comprising two parallel, low noise amplifier branches, and a first combiner (450). The by-pass arrangement includes a second combiner (443), by which the halves (E11, E12) of the received signal are combined immediately after the divider before the amplification. A change-over switch (SW) is then used to select either the signal that has propagated through the amplifier unit and then combined (G·E1) or the signal (E1?) that has been directly combined as the output signal of the front stage. Due to the invention, the noise figure of the front stage is improved and the integration of its structure is facilitated.

Abstract: A broadband antenna element configuration having a radiation pattern useful in an antenna array containing a plurality of driven radiating elements that are spatially arranged is disclosed. The antenna element is coplanarly disposed on a suitable planar substrate of dielectric material. The antenna element utilizes a pair of balanced dipole arm elements symmetrically disposed about the centerline of a balanced feed network. Balanced feed network elements are disposed in a broadside symmetrical configuration on first plane and second plane on each side of the aforementioned dielectric. Disposed proximate to each dipole arm element are partially overlapping, parallel planar, frequency bandwidth expanding microstrip lines. The combination of dipole arms and parasitically coupled microstrip lines provides a broad bandwidth radiating element suitable for use in antenna arrays.

Abstract: An antenna control system in which various antenna elements in a vertical row are coupled by fixed transmission lines to a central feeding point for a common signal. Adjustment of the phase of the common signal is achieved by means of a linearly movable slide having dielectric body portions influencing the signal velocity along said fixed transmission lines. Further, an electrical motor is used for linearly displacing said movable slide with said dielectric body portions.

Abstract: An arrangement for filtering the transmitting signals in a radio device using frequency division duplex. In a radio transmitter, in which the transmitting signal is divided to a plurality of antennas radiating to different sectors, the filtering required in transmitting is mostly carried out by a shared transmitting filter before the transmitting signal is divided. The rest of the filtering is carried out separately on each partial transmitting signal in the reduced transmitting side of the duplex filter. The filters and the divider form an integrated filter unit, in which they are connected to each other by simple coupling elements. The space required for the filters of the antenna end of the radio device is significantly reduced, and the material and assembly costs of the antenna end in production are reduced.

Abstract: A dual polarized antenna element having improved antenna isolation is disclosed by the present invention. The antenna element includes a first feeder for feeding the antenna element in a first polarization direction, and a second feeder for feeding the antenna element in a second polarization direction. According to the present invention, a compensation line is arranged between the first and the second feeders for compensating for an imbalance caused by an essentially capacitive coupling between the first and second feeders. The compensation line is connected to the first and second feeders in close proximity to a radiating part of said antenna element, and has a short electrical length ? and a high impedance relative to an impedance of the first and second feeders, respectively, thereby giving the compensation line an essentially inductive character.

Abstract: An over the air repeater for enhancing wireless communication is provided. The repeater employs a system and method by which strong signals can be prevented from exceeding the repeater's uplink output limits while still providing full operational gain to any concurrently amplified weak signals, while adapting to time slot variations and optionally to frequency hopping variations. Power measurements are performed on each channel with resultant gain changes being performed on delayed versions of those same signals. Digital delay buffers are used to provide adequate processing time to make an accurate determination of the uplink signal levels of each RF carrier. The repeater alternatively monitors the downlink path from the donor base station to determine the frequencies to be processed on the uplink communication.

Abstract: An antenna array employing a combined azimuth and elevation beam angle adjustment electromechanical system is disclosed. The system employs a dual purpose remotely controllable actuator. The actuator is used to adjust azimuth angle of the antenna array and radiation beam tilt of the same. An antenna array employing a combined azimuth, beamwidth and elevation beam angle adjustment electromechanical system is also disclosed.

Abstract: An on frequency repeater for wireless networks with feedback oscillation detection is disclosed. The on frequency repeater includes an automatic gain control loop which samples amplified signal envelope. The automatic gain control loop is monitored and a characteristic saw tooth pattern in the gain control loop indicating feedback oscillation is detected. A nonlinear gain expander circuit may be periodically activated to allow feedback oscillation detection in repeater applications employing linearized amplifiers.

Abstract: An adaptive echo cancellation system and method employing an algorithm suitable for a digital repeater with sub-band filtering is disclosed. Cross- and auto-correlation measurements used to estimate the residual coupling are computed from normalized cross and power spectrums which avoid the problems associated with narrow bandwidth signal components. The normalized cross- and power spectra are additionally masked in frequency to reduce the influence of interfering spectral components outside of the passband of the sub-band filter. Regularization of the iterative estimation process is applied to maintain stability and compensate for the bandwidth reduction associated with the sub-band filter and the spectral mask.

Abstract: A wireless repeater includes an input antenna for receiving an input signal, an output antenna for outputting an amplified signal, and an amplifier for amplifying the received input signal and providing the output amplified signal to the output antenna. Radiated coupling between the input and output antennas causes echoes to be transmitted by the repeater. A filter is used for applying a weighting function to a power spectrum of a measured signal in the wireless repeater thereby obtaining a weighted power spectrum of the measured signal. An internal feedback path is employed for adaptively canceling the echo by implementing an adaptive algorithm based on a autocorrelation of the input signal employing the weighted power spectrum of the measured signal.

Abstract: In embodiments of the present invention improved capabilities are described for a mobile broadband routable internet (MBRI) providing for carrier-grade, networked, broadband, IP-routable communication among a plurality of mobile devices, where the mobile devices may represent a plurality of nodes that are linked together through a mobile ad-hoc network (MANET). Mobile devices may operate as peers in a peer-to-peer network, with full IP routing capabilities enabled within each mobile device, thereby allowing routing of IP-based traffic, including deployment of applications, to the mobile device without need for infrastructure conventionally required for mobile ad hoc networks, such as cellular telephony infrastructure. Full IP-routing to mobile devices may allow seamless integration to the fixed Internet, such as through fixed or mobile access points, such as for backhaul purposes.

Abstract: Presently disclosed are a multichannel receiver and a method of operating it. The multichannel receiver includes a first channel circuit of N channel circuits. The first channel circuit includes a band pass (BP) filter and a gain control feedback circuit configured to adjust a signal provided by the BP filter with respect to a reference voltage.

Abstract: In one aspect, the invention is a method that includes transferring data at an initial mode from a transmitter to a receiver, determining a suggested mode based on the data transferred and determining a count of the data transferred from the transmitter to the receiver. The method also includes transferring the suggested mode and the count to the transmitter and determining a pending mode based on the suggested mode and the count.

Abstract: Communicating between a plurality of nodes includes sensing spectrum activity on at least one channel; generating spectrum awareness data based at least in part on the sensed spectrum activity; determining at least one selected bearer based on the spectrum awareness data; negotiating among nodes to select at least one bearer based on various spectral use criteria.

Abstract: An antenna element architecture containing a dielectric beamwidth compensation perimeter structure around a radiating element is disclosed. A transmitting and receiving antenna element is provided so as to provide a desired azimuth and elevation radiation pattern in the intended polarization without degrading performance of cross polarization. Both single and dual polarization antenna elements can be employed.

Abstract: The present invention relates to a device for adjusting the beam direction of an antenna. The device has a source connection terminal to be connected to a signal source and at least two feed connection terminals to be connected to antenna element feed points. A feed line structure is elongated in a main direction at a distance from and in parallel to a fixed ground plane on at least one side of said feed line structure, wherein a movable dielectric element is located between said feed line structure and said ground plane so as to change the signal phase of signal components being transferred between said source connection terminal and the respective feed connection terminals. The device includes means for allowing said ground plane to be positioned relatively close to said feed line structure without risking accidental contact between said feed line structure and said ground plane.