Abstract: An apparatus includes a directional coupler and an absorptive low pass filter, in which the directional coupler has a first transmission line extending from a first port to a second port and a second transmission line extending from a third port to a fourth port, the first transmission line and the second transmission line configured such that a portion of a signal travelling from the first port onto the first transmission line is coupled to the second transmission line and towards the third port. The second port is connected to the fourth port of the directional coupler via the absorptive low pass filter. When the signal is input into the first port of the directional coupler and output through the third port of the directional coupler, the signal is substantially unattenuated if the frequency of the signal is in a passband of the absorptive low pass filter.

Abstract: A diplexer includes dielectric layers stacked in a lamination direction. The diplexer includes a reference surface extending in a direction orthogonal or substantially orthogonal to the lamination direction, a common terminal on the reference surface, a high-pass circuit including a capacitor, a low-pass circuit including an inductor, a common line connecting the common terminal and a branch portion, a first via connecting the branch portion and the capacitor in the high-pass circuit, and a second via connecting the branch portion and the inductor in the low-pass circuit. The first via extends along the lamination direction from a first layer where the branch portion is located to a second layer where the capacitor in the high-pass circuit is located.

Abstract: Aspects of the subject disclosure may include, for example, a transmission device that includes at least one transceiver configured to modulate data to generate a plurality of first electromagnetic waves in accordance with channel control parameters. A plurality of couplers are configured to couple at least a portion of the plurality of first electromagnetic waves to a transmission medium, wherein the plurality of couplers generate a plurality of second electromagnetic waves that propagate along the outer surface of the transmission medium. A training controller is configured to generate the channel control parameters based on channel state information received from at least one remote transmission device. Other embodiments are disclosed.

Abstract: A phase shifter includes first and second RF terminals, a reference potential terminal; a lumped element LC network connected to the first and second RF terminals and the reference potential terminal, and first and second active semiconductor devices connected to the lumped element LC network and to the reference potential terminal. Each of the first and second active semiconductor devices include a control terminal and first and second output terminals. The lumped element LC network presents a reactance across the first and second RF terminals that shifts the phase of an RF signal as between the first and second RF terminals. The first and second active semiconductor devices are configured to tune the phase shift of the RF signal by controlling the reactance across the first and second RF terminals.

Abstract: An apparatus is provided which comprises: a crystal having an input and an output; a first interconnect line having first and second ends, wherein the first end is coupled to the input; a second interconnect line having first and second ends, wherein the first end is coupled to the output; a first capacitor coupled to the input and ground; and a second capacitor coupled to the second end of the second interconnect line. An apparatus is provided which comprises: a high pass filter; a pair of AC coupling capacitors coupled to the high pass filter; a low pass filter coupled to the pair of AC coupling capacitors; and an analog to digital converter (ADC) coupled to the low pass filter.

Abstract: In accordance with an embodiment, a circuit includes a plurality of filter circuits having a first port, a second port and a third port, where a second port of a first of the plurality of filter circuits is coupled to a first port of a second of the plurality of filter circuits, and each of the plurality of filter circuits includes a first passive filter, a second passive filter, a first coupler and a combining network. The first coupler includes an input port coupled to the first port, an isolated port coupled to the second port, a first phase shifted port coupled to the first passive filter and a second phase shifted port coupled to the second passive filter, and the combining network includes a first input coupled to the first passive filter, a second input coupled to the second passive filter, and an output coupled to the third port.

Abstract: It is provided a waveguide E-plane band-pass filter comprising a tubular, electrically conductive waveguide body. An electrically conductive foil is arranged in the waveguide body and extending along a longitudinal direction of the waveguide body, the foil comprising a plurality of resonator openings. Furthermore, the waveguide body comprises at least one ridge protruding from an inner wall of the waveguide body and extending longitudinally along the longitudinal direction of the waveguide body. The foil is in mechanical contact with said at least one ridge and arranged to divide an inner volume of the waveguide body into two portions. It is also provided a diplexer, a radio transceiver, and a method for filtering a signal using such a filter.

Abstract: The millimeter waveband filter includes: a transmission line that is formed by a waveguide which propagates electromagnetic waves with a predetermined frequency range of a millimeter waveband from one end to the other end in a TE10 mode; and a pair of radio-wave half mirrors that are disposed opposite each other with a space interposed therebetween so as to block the inside of the transmission line and have planar shapes and a characteristic of transmitting a part of the electromagnetic waves with the predetermined frequency range and reflecting a part thereof. In the electromagnetic waves incident from the one end side of the transmission line, a frequency component centered on a resonant frequency of a resonator, which is formed between the pair of radio-wave half mirrors, is selectively output from the other end of the transmission line.

Abstract: The millimeter waveband filter includes: a transmission line that is formed by a waveguide which propagates electromagnetic waves with a predetermined frequency range of a millimeter waveband from one end to the other end in a TE10 mode; and a pair of radio-wave half mirrors that are disposed opposite each other with a space interposed therebetween so as to block the inside of the transmission line and have planar shapes and a characteristic of transmitting a part of the electromagnetic waves with the predetermined frequency range and reflecting a part thereof. In the electromagnetic waves incident from the one end side of the transmission line, a frequency component centered on a resonant frequency of a resonator, which is formed between the pair of radio-wave half mirrors, is selectively output from the other end of the transmission line.

Abstract: Aspects of the subject disclosure may include, for example, a system that performs operations including receiving electromagnetic waves on an outer surface of a transmission medium having a non-hybrid wave mode and a cutoff frequency, detecting a degradation of a signal quality of the electromagnetic waves, generating adjusted electromagnetic waves having a hybrid wave mode and a non-optical frequency range responsive to the detecting, and directing the adjusted electromagnetic waves having the hybrid wave mode and the non-optical frequency range to the outer surface of the transmission medium for guiding propagation of the adjusted electromagnetic waves without utilizing an electrical return path. Other embodiments are disclosed.

Abstract: There are provided a transformer including inductors, and variable capacitors. Capacitance values of the variable capacitors are controlled by a control signal. One end of the first inductor is connected to a reference potential, the first variable capacitor is connected in series between the other end of the first inductor and a first terminal, the second variable capacitor is connected in series between one end of the second inductor and a second terminal, the third variable capacitor is connected in series between the other end of the second inductor and a third terminal. The capacitance values of the variable capacitors are changed by the control signal to obtain a desired pass phase, a loss is small, and both functions of a single-phase-differential conversion and a phase shifter are realized.

Abstract: Aspects of the subject disclosure may include, for example, a system that performs operations including detecting a signal degradation of electromagnetic waves guided by a transmission medium, and adjusting at least one phase of signal components of the electromagnetic waves to produce adjusted electromagnetic waves having a hybrid wave mode and a non-optical frequency range to mitigate the signal degradation. Other embodiments are disclosed.

Abstract: Aspects of the subject disclosure may include, for example, a system that performs operations including receiving electromagnetic waves on an outer surface of a transmission medium having a non-hybrid wave mode and a cutoff frequency, detecting a degradation of a signal quality of the electromagnetic waves, generating adjusted electromagnetic waves having a hybrid wave mode and a non-optical frequency range responsive to the detecting, and directing the adjusted electromagnetic waves having the hybrid wave mode and the non-optical frequency range to the outer surface of the transmission medium for guiding propagation of the adjusted electromagnetic waves without utilizing an electrical return path. Other embodiments are disclosed.

Abstract: An electronic device comprises a divider and a first filter. The divider comprises a first terminal for inputting a high-frequency signal, a second terminal coupled to the first terminal, and third and fourth terminals for distributing thereto the signal inputted from the first terminal. The first filter is coupled to the second terminal.

Abstract: A directional coupler includes a first conductive track, a second conductive track, and a conductive structure. The conductive structure includes a first partial region that is arranged nearer to the first conductive track than the first conductive track is to the second conductive track. The conductive structure also includes a second partial region that is arranged nearer to the second conductive track than the first conductive track is to the second conductive track.

Abstract: A filter block comprising a hybrid filter, the hybrid filter comprising a first signal splitter having a first input port and a first output port; a second signal splitter having a first input port and a first output port; each of the first and second splitters having first and second connection ports; the two first connection ports being connected together by a first signal path comprising a first filter; the second two connection ports being connected together by a second signal path comprising a second filter; the first and second signal paths each further comprising a transformer connected between the filter and one of the first and second signal splitters.

Abstract: The directional coupler supports ultra high bandwidth of 5600 MHz (from 400 MHz to 6 GHz) in compact structure and also provides high directivity of (>15 dB). The coupler uses a two stage micro-strip directional coupler for a frequency range of 400 MHz to 6 GHz, where the first stage supports a frequency of operation from 0.4 GHz to 1 GHz and the second stage supports a frequency of operation from 1 GHz to 6 GHz and the required coupled port can be chosen using a radio frequency switch as required by the application used in.

Abstract: A directional dual distributed coupler including: a first conductive line between first and second ports, intended to convey a signal to be transmitted in a first frequency band; a second conductive line coupled to the first one; a third conductive line between third and fourth ports, intended to convey a signal to be transmitted in a greater frequency band than the first one; a fourth conductive line coupled to the third one; and at least one diplexer connecting, on the side of the second and fourth ports, the respective ends of the second and fourth lines to a fifth port.

Abstract: A band combining filter for filtering a microwave signal having at least one band edge at a band edge transition frequency. The filter comprises a plurality of filter sections. Each filter section comprising 3dB hybrid couplers having input ports and output ports and resonators connected between the input ports and the output ports of the couplers. The filter sections are connected in cascade such that the outputs of one filter section are connected to the inputs of the next filter section in the cascade. A subset of the filter sections are high Q filter sections with the Q values of the resonators of those filter sections having values each of which are at least a factor of three higher than the Q values of the resonators of the remaining filter sections.

Abstract: A balun transformer includes an unbalanced terminal, two balanced terminals, a directional coupler, a low pass filter, and a high pass filter. The directional coupler includes first, second, third and fourth terminals. The first terminal is connected to the unbalanced terminal. A predetermined phase difference exists between the output signal of the second terminal and the output signal of the third terminal. The second terminal is connected to the first terminal by a line constituting the directional coupler. The low pass filter is connected between the second terminal and one of the balanced terminals. The high pass filter is connected between the third terminal and the other balanced terminal.

Abstract: This invention describes a method by which the output power of a circuit or system at any point can be efficiently and cost effectively sampled in a simple and broadband fashion for processing in a closed loop system for applications such as power level control in very broadband circuits. A divider circuit consisting of a selection of passive lumped elements is used to create a very broadband means of sampling the RF power level at any point in a transmission line. Unlike prior art schemes of this nature, this circuit does not rely upon extremely accurate element values and minimization of parasitic reactances. Used in conjunction with a balanced detector-logarithmic or other amplifier combination this invention result in a very broadband low cost simplified realization of the traditional costly bandwidth limited directional coupler-detector combination.

Abstract: Techniques, antenna systems and apparatus based on composite right and left handed (CRLH) metamaterial (MTM) structures to couple CRLH MTM circuits to transistors to amplify signals in wireless RF receivers and transmitters.

Abstract: A distributed multiband coupling circuit including: a number n of first and of second terminals equal to the number of frequency bands; a third terminal and a fourth terminal; a number n of distributed couplers equal to the number of frequency bands, all couplers being identical and sized according to the highest frequency band, and each coupler including a first conductive line between first and second ports intended to convey a signal to be transmitted in the concerned frequency band, and a second conductive line coupled to the first one between third and fourth ports; a first set of resistive splitters in cascade between the third ports of the couplers, a terminal of the splitter associated with the first coupler being connected to the third terminal of the coupling circuit; and a second set of resistive splitters in cascade between the fourth ports of the couplers, a terminal of the splitter associated with the first coupler being connected to the fourth terminal of the coupling circuit.

Abstract: A directional coupler according to the present invention includes a primary line for transmitting a transmission signal; an input port for inputting the transmission signal to the primary line; an output port for outputting the transmission signal from the primary line; a secondary line for electromagnetically coupling with the primary line to extract part of the transmission signal; a coupling port provided at one end of the secondary line; an isolation port provided at the other end of the secondary line; and a low pass filter unit having a function of low pass filter, disposed between the secondary line and the coupling port.

Abstract: A method of tuning the stopband attenuation of an absorptive bandstop filter having at least a first and second resonator, where the first resonator includes a first tuning element that exhibits a first resonant frequency, the second resonator includes a second tuning element that exhibits a second resonant frequency, and the tuning elements are used to adjust the corresponding resonant frequencies, includes 1) adjusting the first resonant frequency using the first tuning element; and 2) adjusting the second resonant frequency using the second tuning element, such that both resonant frequencies are coordinated to obtain a selected stopband attenuation level and to thus realize a frequency-selective variable attenuator.

Abstract: According to one or more embodiments, a directional filter assembly (10) comprises a multi-port filter circuit (12) for combining or separating signals in specified pass-bands and an isolated port (20) having a resistive load (22), for absorbing out-of-band signals. The assembly further includes a reflective protection device (24) configured to protect the resistive load (22) from being overpowered by out-of-band signal power, based on being configured to reflect or not reflect the out-of-band signals in dependence on the level of out-of-band signal power. In at least one embodiment, the directional filter assembly is configured as a microwave transmission assembly, such as is used for combining signals from two or more base stations, for transmission from a common antennae assembly.

Abstract: One or more carrier signals in a multiple-carrier UE transmitter are frequency-adjusted to account for an estimated error in the separation frequency between the transmitted carrier signals. The adjustment is applied when generating the UL signals for the respective carrier frequencies in digital baseband of the UE. In one embodiment, one or more of the modulators that apply the carrier separation frequency additionally apply a frequency correction. In another embodiment, first mixers apply the carrier separation frequency to each different carrier signal. One or more carrier signal paths include a second mixer applying a frequency correction to the carrier signal. The RF modulation frequency may also be adjusted to partially compensate for the estimated carrier separation frequency error.

Abstract: A directional dual distributed coupler including: a first conductive line between first and second ports, intended to convey a signal to be transmitted in a first frequency band; a second conductive line coupled to the first one; a third conductive line between third and fourth ports, intended to convey a signal to be transmitted in a greater frequency band than the first one; a fourth conductive line coupled to the third one; and at least one diplexer connecting, on the side of the second and fourth ports, the respective ends of the second and fourth lines to a fifth port.

Abstract: A band combining filter for passing signals in a communications band includes a plurality of cascaded directional filters. Each directional filter has at least two inputs and at least two outputs. The nth directional filter is arranged such that output signals O1 and O2 from the first and second outputs are related to input signals I1, I2 to the first and second inputs by the relation ( O 1 O 2 ) = ( R n ? ? 1 T n ? ? 2 T n ? ? 1 R n ? ? 2 ) ? ( I 1 I 2 ) with R and T being reflection and transmission functions respectively. The directional filters are connected in a cascade with the first and second inputs of the nth directional filter being connected to the first and second outputs of the (n?1)th directional filter respectively in the cascade. At least one of the reflection functions Rn overlaps with the corresponding reflection function Rn?1 within the communication band but is different thereto.

Abstract: A directional coupler that has a degree of coupling that is close to constant and is to be used in a predetermined frequency band includes a main line between a first outer electrode and a second outer electrode. A sub-line is provided between a third outer electrode and a fourth outer electrode and is electromagnetically coupled with the main line. A low pass filter is provided between the third outer electrode and the sub-line and has a characteristic in which attenuation increases with increasing frequency in a predetermined frequency band.

Abstract: A duplexer includes a common terminal, receiving filters, a transmitting filter, and a hybrid having four terminals (terminals 1 to 4). A first terminal (terminal 1), which is one of the four terminals of the hybrid is connected to the common terminal, the receiving filters are connected to a second terminal and a third terminal to which a signal is transmitted if it is input from the first terminal, and a transmitting filter is connected to a fourth terminal (terminal 4) of the hybrid. Thus, it is possible to improve the isolation of the duplexer, while avoiding an increase in the number of parts as well as greater complexity.

Abstract: In a timing analysis apparatus for use in a semiconductor integrated circuit, which analyzes operation timing of a semiconductor integrated circuit having a logic gate circuit including a plurality of logic gates, a controller detects at least one of a power supply voltage and a ground voltage of a power supply, decomposes the noise waveform into frequency components, classifies the frequency components into low-frequency components lower than a predetermined threshold frequency and high-frequency components higher than the threshold frequency, calculates a static delay time of each of the logic gates due to the low-frequency components, calculates a dynamic delay time of each of the logic gates due to the high-frequency components, and determines a delay time of each of the logic gates by synthesizing the calculated respective delay times.

Abstract: A Radio Frequency (RF) filter configured by combining a hybrid coupler with a general filter, for having different characteristics from original characteristics of a general filter is provided, in which a coupler receives an input signal through a first port, divides the input signal, outputs the divided signals through second and third ports, combines signals received through the second and third ports according to phases of the signals, and outputs the combined signal through the first port or as an output signal of the RF filter through a fourth port, and a first filter unit has a first port connected to the second port of the coupler and a second port connected to the third port of the coupler, for having a predetermined frequency filtering characteristic.

Abstract: A distributed multiband coupling circuit including: a number n of first and of second terminals equal to the number of frequency bands; a third terminal and a fourth terminal; a number n of distributed couplers equal to the number of frequency bands, all couplers being identical and sized according to the highest frequency band, and each coupler including a first conductive line between first and second ports intended to convey a signal to be transmitted in the concerned frequency band, and a second conductive line coupled to the first one between third and fourth ports; a first set of resistive splitters in cascade between the third ports of the couplers, a terminal of the splitter associated with the first coupler being connected to the third terminal of the coupling circuit; and a second set of resistive splitters in cascade between the fourth ports of the couplers, a terminal of the splitter associated with the first coupler being connected to the fourth terminal of the coupling circuit.

Abstract: A loop directional coupler having a first waveguide, particularly a hollow, planar, or a coaxial conductor in the form of a half loop antenna having first and second antenna branches for the contact-free extraction of an incoming signal “a” on a second waveguide and a returning signal “b” on the second waveguide. The first antenna branch is connected to a first input of a first network and the second antenna branch is connected to a second input of the first network, the first network having a first power splitter at the first input and a second power splitter at the second input for dividing the signal present at each antenna branch, the first network having a first adder adding the signals of the first and second power splitters to each other, and a first subtractor subtracting the signals of the first and second power splitters from each other.

Abstract: The invention presents a filter combiner, in particular for mobile communications applications, adapted to be connected to an antenna (12), comprising a first directional coupler (13), connected to at least one first filter (15, 15a, 15b), to an antenna branch (12a), to at least one second filter (17, 17a, 17b), and to a first signal branch (20), the combiner also comprising a second directional coupler (21), connected to the at least one first filter (15, 15a, 15b), to a second signal branch (25), and to the at least one second filter (17, 17a, 17b). Further, the first directional coupler (13) is adapted to be connected to the first signal branch (20) via at least one third filter (29, 29a, 29b).

Abstract: A phased-array antenna filter and diplexer for a super economical broadcast system are provided. The filter and diplexer includes a signal divider tee diplexer, a receive filter and a transmit filter. The diplexer includes a tee branch point, an antenna port, a transmit port and a receive port. The receive filter includes a flat, multi-pole bandpass filter, an input port and an output port, where the input port is coupled to the diplexer receive port to define a receive signal path, from the tee branch point to the receive input port, that has a length of approximately one quarter receive wavelength. The transmit filter includes a folded, multi-pole bandpass filter, an input port and an output port, where the output port is coupled to the diplexer transmit port to define a transmit signal path, from the tee branch point to the transmit output port, that has a length of approximately one quarter transmit wavelength.

Abstract: A band combining filter for passing signals in a communications band includes a plurality of cascaded directional filters. Each directional filter has at least two inputs and at least two outputs. The nth directional filter is arranged such that output signals O1 and O2 from the first and second outputs are related to input signals I1, I2 to the first and second inputs by the relation ( O 1 O 2 ) = ( R n ? ? 1 T n ? ? 2 T n ? ? 1 R n ? ? 2 ) ? ( I 1 I 2 ) with R and T being reflection and transmission functions respectively. The directional filters are connected in a cascade with the first and second inputs of the nth directional filter being connected to the first and second outputs of the (n?1)th directional filter respectively in the cascade.

Abstract: The present invention concerns a frequency diplexer with an input port and a first and a second output ports, comprising two directional couplers (14 and 15), an unique filter (16) that entails either a first or a second frequency response, and, a first and a second T splitters (19, 40).

Abstract: Power combining methods and devices for tunnel diode oscillators using the infinite wavelength phenomenon observed in composite right/left-handed (CRLH) meta-material lines are described. One implementation utilizes a series combiner composed of zero degree lines, with each oscillator output port connected directly to the line and combined in-phase, to equally combine the power in phase. In a second implementation, a section of zero degree transmission line implements a stationary wave resonator with oscillators loosely coupled to the resonator, where the wave amplitude and phase are constant along the line. In one test of this second implementation a maximum power combining efficiency of 131% was obtained with the zeroth order resonator with two tunnel diodes oscillators at 2 GHz.

Abstract: The invention presents a filter combiner, in particular for mobile communications applications, adapted to be connected to an antenna (12), comprising a first directional coupler (13), connected to at least one first filter (15, 15a, 15b), to an antenna branch (12a), to at least one second filter (17, 17a, 17b), and to a first signal branch (20), the combiner also comprising a second directional coupler (21), connected to the at least one first filter (15, 15a, 15b), to a second signal branch (25), and to the at least one second filter (17, 17a, 17b). Further, the first directional coupler (13) is adapted to be connected to the first signal branch (20) via at least one third filter (29, 29a, 29b).

Abstract: A filter circuit is constructed as a triplex filter having a high-pass filter, a low-pass filter with attenuation in the passband, and a second low-pass filter without attenuation in the passband. The filter circuit has a frequency response with a high-pass portion, a flat loss portion, and a low-pass portion. Attenuation in the flat loss portion is uniform and is predetermined via selection of filter components. The filter circuit is useful in a bidirectional CATV system in which performance is improved by selectable attenuation of a first source of return path signals but without attenuation of a second source of return path signals.

Abstract: A band combining filter comprising a plurality of cascaded directional filters, each directional filter having at least two inputs and at least two outputs, the nth directional filter being arranged such that the output signals O1 and O2 from the first and second outputs are related to the input signals I1, I2 to the first and second inputs by the relation ( O 1 O 2 ) = ( R n ? ? 1 T n ? ? 2 T n ? ? 1 R n ? ? 2 ) ? ( I 1 I 2 ) with R and T being reflection and transmission functions respectively, characterised in that the directional filters are connected in a cascade with the first and second inputs of the nth directional filter being connected to the first and second outputs of the (n-1)th directional filter respectively in the cascade.

Abstract: An absorptive bandstop filter includes at least two frequency-dependent networks, one of which constitutes a bandpass filter, that form at least two forward signal paths between an input port and an output port and whose transmission magnitude and phase characteristics are selected to provide a relative stopband bandwidth that is substantially independent of the maximum attenuation within the stopband and/or in which the maximum attenuation within the stopband is substantially independent of the unloaded quality factor of the resonators. The constituent network characteristics can also be selected to provide low reflection in the stopband as well as in the passband. The absorptive bandstop filter can be electrically tunable and can substantially maintain its attenuation characteristics over a broad frequency tuning range.

Abstract: A waveguide directional filter for combining multiple high power UHF television broadcasting transmitters on to a common antenna. The directional filter arrangement includes an input waveguide, an output waveguide and an interconnected cascade assembly of two or more cavity resonators. The input and output waveguides are each aperture-coupled to an end cavity resonator of the cascade assembly. The edges of each aperture incorporate inwardly extending curved protrusions of a characteristic shape. Alternatively or additionally, at least one pair of non-adjacent cavity resonators are coupled by at least one additional coupling element incorporating an external transmission line.

Abstract: An adjustable low pass filter and directional coupler used in microwave communication are combined to reduce the size of the microwave circuit. The low pass filter portion and coupling portion are made independently tunable with a plurality of varactors and variable reactance circuits connected to ground.

Abstract: A power detector for measuring the average power, without constant voltage, of modulated or unmodulated high frequency or microwave signals is described. The power detector includes a signal line connected to a high frequency input. A detection line is capacitively and/or inductively coupled to the signal line and, seen in the longitudinal direction, is connected to the signal line. The signal is tapped from the detection line at two or more detection positions which are staggered in the longitudinal direction.

Abstract: Multi-tuner receivers with cross talk reduction are disclosed. In one embodiment, a multi-tuner receiver with cross talk reduction includes a low noise amplifier, a set of interstage filters and a set of corresponding tuners. In an alternative embodiment, a multi-tuner receiver with cross talk reduction includes a passive splitter, a set of interstage filters and a set of corresponding tuners. The interstage filters can be low-pass, high-pass or band-pass filters depending on the particular frequency range of interest. Typical embodiments can have two or three tuners, however, the invention applies to multi-receiver tuners with more than three tuners. The multi-tuner receivers can be used within television, cable set top boxes and other devices that receive multiple video signals.

Abstract: A radio frequency switching apparatus wherein a filter for a transmitter module passes a transmission frequency to an antenna in a transmission mode and isolates the antenna and the transmitter module from each other in a reception mode. The radio frequency switching apparatus comprises a filter connected between the transmitter module and the antenna for passing a transmitted signal from the transmitter module to the antenna in the transmission mode. The filter also acts to cut off a reception frequency in the reception mode. The switching apparatus further comprises a first switching device for isolating the transmitter module and the antenna from each other in the reception mode, and a second switching device for isolating the antenna and a receiver module from each other in the transmission mode. No separate ¼ wavelength strip line is required, making the circuitry of the switching apparatus simpler and, thus, the size thereof smaller.

Abstract: A filter circuit filters unnecessary frequency components within a signal. The filter circuit includes a first and a second line pattern and a closed loop pattern portion. The first line pattern has two ends and one end thereof is connected to an input terminal and the other is opened or grounded. The second line pattern has two ends and one end thereof is connected to an output terminal and the other being opened or grounded. The closed loop pattern portion, which is interposed between the first and the second line pattern, has two or more closed loop patterns and each of the closed loop patterns has an electromagnetic coupling portion coupled to each of the first and the second line pattern.