70results about How to "Minimizing insertion loss" patented technology

An optical fiber coupler capable of providing a low loss, high coupling coefficient interface between conventional optical fibers and optical waveguide devices is provided. The novel coupler, which may be polarization maintaining, if a polarization maintaining preform is used in its fabrication includes a core, a cladding, a first end for interfacing with an optical fiber and a second end for interfacing with an optical waveguide device. The sizes of the core and cladding are gradually reduced from the first end to the second end in accordance with a predetermined reduction profile. Various parameters, such as refractive indices and sizes of the core and cladding and the reduction profile are selected to produce a low numerical aperture at the first end and a high numerical aperture at the second end, while advantageously minimizing insertion loss and maximizing the coupling coefficient at each end. In another embodiment, the novel coupler includes a secondary cladding which is also reduced between the first and second ends to improve the strength of the coupler structure at the second end. In yet another embodiment, one or two novel couplers are formed along with a chiral fiber based optical waveguide device as a single continuous element. The optical fiber preform used to fabricate the novel optical fiber coupler can be etched prior to fabrication to facilitate application of the reduction profile.

Catheter apparatus comprises a coaxial cable having proximal and distal ends. The cable includes a hollow center conductor, an outer conductor and an electrically insulating layer between the conductors. An antenna is at the distal end of the cable, and a diplexer is connected to the cable, the diplexer including a transmit path for connecting the antenna to a transmitter which transmits first frequency signals and a receive path for connecting the antenna to a receiver which detects second frequency signals the diplexer isolating the signals on the two paths from one another. A transmission line connects the cable to the diplexer, the transmission line having a segment with a tubular inner conductor one end of which is connected to the center conductor and a second end of which is adapted for connection to a coolant source, the center and inner conductors forming a continuous coolant pathway.

A tunable RF filter comprises a signal transmission path having an input and output, a plurality of resonant elements disposed along the signal transmission path between the input and output, and a set of non-resonant elements coupling the resonant elements together to form a stop band having a plurality of transmission zeroes corresponding to respective frequencies of the resonant elements, and at least one sub-band between the transmission zeroes. The set of non-resonant elements comprises a first plurality of non-resonant elements respectively coupled in parallel with the resonant elements, and a second plurality of non-resonant elements respectively coupled in series with the resonant elements. The first plurality of non-resonant elements comprises at least one variable non-resonant element for selectively introducing at least one reflection zero within the stop band to create a pass band in one of the one sub-band(s) without varying any of the second plurality of non-resonant elements.

A tunable radio frequency (RF) filter is provided. The RF filter comprises a signal transmission path having an input and an output, a plurality of resonant elements disposed along the signal transmission path between the input and the output, and a plurality of non-resonant elements coupling the resonant elements together. The resonant elements are coupled together to form a stop band having a plurality of transmission zeroes corresponding to respective frequencies of the resonant elements, and at least one sub-band between the transmission zeroes. The non-resonant elements comprise at least one variable non-resonant element for selectively introducing at least one reflection zero within the stop band to create a pass band in one of the sub-bands(s). The variable non-resonant element(s) may be configured for displacing the reflection zero(es) along the stop band to selectively move the pass band within the one sub-band or within selected ones of the sub-bands.

A model train and layout control system based on on-board sound and locomotive modules, new signaling methods, bi-directional communication, environmental sound, turnout control, train location methods, computer interaction and accessory control, by adding components to existing technology. AC power signal waveforms are variously altered to convey digital command words.

Process and device for compensating the low frequency magnetic field in an inductive signal coupling unit. According to the invention the coupling unit comprises a ferromagnetic core (30) which encloses a conductor through which a low frequency current (1) is circulating in order to inject thereon a high frequency signal. Current (1), circulating through the conductor or the magnetic field (3) produced in the coupling unit, is detected, and a compensating current is obtained based on the value obtained in the detection carried out, and the compensating current obtained in the coupling unit is injected through a low pass filter (9) to produce a magnetic field (4) equal and opposite to the produced by current (1) of the conductor in the coupling unit, and thereby avoiding the saturation of the magnetic core (30) without adding insertion loss. In general the invention is applied to communication systems which require the injection of a radio frequency signal on a conductor, and in particular in systems which use the electricity grid as the transmission medium.

A dual-mode front end module (FEM) includes an antenna switch module (ASM), a first filtering unit which filters signals of a first type that are outputted from the ASM, a single pole double throw (SPDT) switch, a second filtering unit which filters signals of a second type that are inputted to or outputted from the SPDT switch, and at least one antenna port for transmitting and receiving at least one of the signals of the first type and the signals of the second type.

A high-frequency module constituted by an integral laminate for handling a plurality of transmitting / receiving systems having different passbands comprises (a) a switch module part for branching higher-frequency signals and lower-frequency signals and switching connection to the transmitting systems and the receiving systems, (b) a high-frequency amplifying circuit module part, and (c) a phase-adjusting circuit disposed between the switch module part and the high-frequency amplifying circuit module part, wherein the phase matching between the switch module part and the high-frequency amplifying circuit module part via the phase-adjusting circuit is adjusted to conjugate matching in a fundamental frequency band, while it is adjusted in a nonconjugate matching range in n-th frequency bands, wherein n is an integer of 2 or more.

A monolithic photonic integrated circuit (PIC) chip where the active waveguide cores of the modulated sources of the PIC are multiple quantum wells (MQWs) and the passive waveguide cores of an optical combiner are a bulk layer or material. The cores of the waveguide cores may be a quaternary such as InGaAsP or InAlGaAs.

A waveguide diplexer having an electric plane T-junction structure with a resonant iris is disclosed. The waveguide includes: a waveguide having a predetermined shaped cross section; a transmitting filter for preventing to generate a harmonic band and a higher mode in a receiving band by changing impedance to have a low pass characteristic inside the waveguide; a receiving filter for minimizing an insertion loss by changing impedance to have a bandpass characteristic inside the waveguide; an electric plane T-junction for isolating / combining a transmitting signal and a receiving signal without electric interference by connecting the transmitting filter and the receiving filter, and minimizing interference of a frequency transmitted / received through the transmitting filter and the receiving filter; and an impedance converter for differentiating a transmitting port and a receiving port with minimum electric interference to the transmitting filter and the receiving filter by changing the impedance.