694 results about "Transmission zeros" patented technology

A method of constructing a band-stop filter comprises designing a band-stop filter including a signal transmission path, resonant elements disposed along the signal transmission path, and non-resonant elements coupling the resonant elements together to form a stopband having transmission zeroes corresponding to respective frequencies of the resonant elements. The method further comprises changing the order in which the resonant elements are disposed along the signal transmission path to create different filter solutions, computing a performance parameter for each filter solution, comparing the performance parameters to each other, selecting one of the filter solutions based on this comparison, and constructing the band-stop filter using the selected filter solution. Another RF band-stop filter comprises resonant elements coupled together to form a stopband, wherein at least two of the resonant elements have third order IMD components different from each other, such that the IMD components are asymmetrical about the stopband.

An RF filter, e.g. RF cavity filter for adjusting coupling amount or transmission zero is disclosed. The RF filter includes a housing member in which cavities are defined by walls, resonators located in the cavities, a cover combined with an upper surface of the housing member, a first tuning element inserted into a first cavity of the cavities through the cover, and a second tuning element inserted into a second cavity of the cavities through the cover. Here, the first tuning element and the second tuning element are connected electrically.

A voltage probe includes a first signal lead configured to receive a first signal from a device under test, a first probe-tip network that is coupled to the first signal lead and that has a frequency response that includes a first transmission zero, a first compensation network that is coupled to the first probe-tip network and that has a frequency response that includes a first transmission pole, a second signal lead configured to receive a second signal from the device under test, a second probe-tip network that is coupled to the second signal lead and that has a frequency response that includes a second transmission zero, a second compensation network that is coupled to the second probe-tip network and that has a frequency response that includes a second transmission pole, and a differential amplifier circuit that is coupled to the first compensation network and to the second compensation network, and that is configured to provide a third signal that is responsive to the first signal and to the second signal. Methods and other systems for providing electrical connections to devices under test are disclosed.

According to the general concept disclosed herein, a circuit for adaptive matching of a load impedance to a predetermined load-line impedance of a load-line connected to a power amplifier output includes a fixed matching network between the power transistor and an adaptive matching network, whereby the fixed matching network acts as an impedance inverter which results in a relatively low insertion loss at high power. Results indicate that the impedance-inverting network can be used over more than a factor of 10 in impedance variation. Further, the usage of the fixed matching network, close to the power transistor, allows for the implementation of transmission zeros and/or for a well defined load impedance at a predetermined harmonic frequency, independent of the (variable) load impedance at the fundamental frequency.

A planar antenna disposed on a plate having a first surface and a second surface is provided. The planar antenna includes a metal layer, an antenna body, a stepped impedance device, a coupling device and a matching device. The metal layer is disposed on the first surface and has a slot line exposing the first surface. The antenna body, the stepped impedance device, the coupling device and the matching device are disposed on the second surface. The antenna body is corresponding to a surrounding of the metal layer except a feed end thereof, the stepped impedance device and the matching device are corresponding to the metal layer, and the coupling device is corresponding to the slot line. The matching device is coupled between the coupling device and the feed end. The stepped impedance device has a transmission zero in a radio frequency band operated by the antenna body.

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.

The invention discloses a stacked type three-order substrate integrated waveguide filter. The stacked type three-order substrate integrated waveguide filter comprises a top surface metal layer, a first dielectric substrate, a first middle metal layer, a second dielectric substrate, a second middle metal layer, a third dielectric substrate and a bottom surface metal layer which are stacked and distributed in sequence, wherein a first resonant cavity, a second resonant cavity and a third resonant cavity are formed in the first dielectric substrate, the second dielectric substrate and the third dielectric substrate respectively; an input port is formed in the top surface metal layer; an output port is formed in the bottom surface metal layer; the first middle metal layer is used for adjusting the magnetic coupling coefficient between the first resonant cavity and the second resonant cavity to obtain a first transmission zero point; and the second middle metal layer is used for adjusting the magnetic coupling coefficient between the second resonant cavity and the third resonant cavity to obtain a second transmission zero point. The stacked type three-order substrate integrated waveguide filter provided by the invention, by adjusting the electromagnetic coupling strength and obtaining extra transmission zero points, greatly improves frequency selection and harmonic suppression characteristics without changing the existing dimensions.

This invention provides the design of cross coupling in filter and method for preparing the same. Which is based on coupling relation mode and determining transmission zero number and relative position by analyzing relative phase shifting relation, according to cross coupling realizing method selecting and optimizing cross coupling parts, based on filter adjusting method determining resonance frequency distribution property, coupling parts parameter, so quick and accurate debugging resonator unit and coupling part parameters.

The invention discloses a source end coupling microstrip filter which comprises a T-shaped resonator, an input coupling feed line, an output coupling feed line and an interfinger coupling line, wherein the T-shaped resonator is provided with two open-circuit branch sections and a short-circuit branch section, the two open-circuit branch sections form both sides of a U-shaped microstrip line, the short-circuit branch section is arranged at the bottom end of the U-shaped microstrip line, the short-circuit end of the short-circuit branch section is provided with a grounding through hole, and thesum of the lengths of the two open-circuit branch sections and the short-circuit branch section is a one half wavelength; the input coupling feed line and the output coupling feed line are coupled with the open-circuit branch sections at the inner sides of the open-circuit branch sections of the T-shaped resonator; and the interfinger coupling line is positioned in the T-shaped resonator and is arranged between the input coupling feed line and the output coupling feed line. The invention is provided with a plurality of controllable transmission zero points and has the advantages of flexible design, small volume, small insertion loss and the like.

The invention discloses a double frequency band filter of a SIR coaxial cavity. The double frequency band filter of the SIR coaxial cavity comprises a CQ-type topological structure formed by coupling of a coaxial SIR in magnetic and galvanic modes. The coaxial SIR is composed of a rod-shaped inner layer metal transmission line, an outer layer barrel-shaped metal wall and a middle medium layer, wherein the outer layer barrel-shaped metal wall shares the same axis with the inner layer metal transmission line which is formed by connecting of two coaxial transmission lines with different diameters. A terminal opening end coaxial borehole is formed at the top end of a terminal opening end of the metal transmission line, and a tuning screw is placed at the top end of the terminal opening end of the metal transmission line to tune. The double frequency band filter is provided with the CQ-type topological structure of 8 cavities, two transmission zeroes are generated on the outside of a double frequency band, so that out-of-band suppression performances are greatly improved. Compared with a traditional duplexer, the double frequency band filter is improved on the aspects of size miniaturization and design complexity in quality mode. The double frequency band filter has the advantages of being small, low in insertion loss, high in double frequency selection properties and the like. The demands on filter performances by a modern communication system are met, and the double frequency band filter can be widely applied in double frequency band mobile communication systems.

A fully-integrated continuous-time active complex bandpass IF filter that may contain transmission zeros yielding much sharper roll-off than that of an all-pole filter is implemented using transconductors and capacitors only. Each of the filter second-Order sections realizes a pair of complex poles and a may realize a double imaginary axis zero. Since the transconductors are electronically tunable the positions of filter zeros and poles are adjustable using an automatic tuning system. In each filter section the value of different transconductors are modified to separately change the pole frequency, its Q-factor and the zero frequency. Each pole and zero are separately tuned, which achieves a higher level of tuning accuracy than in case where all poles and zeros were adjusted simultaneously.

The invention discloses a high-efficiency wideband power amplifier with a band-pass filter response function. The high-efficiency wideband power amplifier comprises a DC biasing circuit, a power amplification transistor, an input match circuit and an output match circuit. A microstrip line band-pass filter with different port impedances and a section of tuning microstrip line are designed to be used as the output match circuit of the power amplifier, the function of the filtering is achieved, meanwhile, the circuits are made to have the band-pass filter response characteristic, and two transmission zeros are generated on the edge of a passband. Compared with a traditional cascade circuit of a power amplifier and a filter, due to the fact that the microstrip line band-pass filter is used as the output match circuit, the entire circuit is small in size, small in loss and wide in working band, and high edge selectivity is achieved due to the two transmission zeros. The high-efficiency wideband power amplifier with the high-pass filter response function is achieved, and testing result validation is provided.

The invention discloses a novel multifunctional reconfigurable filter based on a principle of signal interference. The multifunctional reconfigurable filter comprises an upper micro-strip structure, an intermediate dielectric plate, and a lower grounded metal, wherein the upper micro-strip structure comprises two input/output feeder lines, five microstrip lines, one pair of parallel coupling lines, six blocking capacitors, five biasing resistors, five PIN pipes and four short circuit grounded through holes. By adding a switch for controlling on-off in a transmission line, selection of path of the transmission line can be controlled, and thus multiple filter modes which are switchable can be achieved. The achieved filter modes comprise an ultra-wideband band-pass filter mode (UWB-BPF), a narrow-band band-pass filter mode (NB-BPF) and an ultra-wideband band stop filter mode (UWB-BSF) respectively. A pass band mode is formed by leading a transmission zero into a terminal short-circuit resonator; a stop band mode is formed by forming a wide stop band through superposition and subtraction of two-way signals according to the principle of signal interference. All the three modes can be achieved and adjusted, the structures are simple, features are good, and integration of circuits and packaging of systems can be easily achieved.

The invention discloses a complementary opening resonance ring and defect ground structure half module substrate integrated waveguide dual-band filter. The dual frequency-band filter is realized by using two resonators. The dual frequency-band filter is a complementary opening resonance ring defect ground structure which is characterized in that a top layer metal is arranged on a medium substrate, a top layer metal ground is arranged on a grounding metal surface, a complementary opening resonance ring structure is etched in the top layer metal and a grounding metal paster is etched. A line of metal through holes, microstrip lines, impedance matching units, an input feed wire and an output feed wire are arranged at one edge of the top layer metal. The complementary opening resonance ring structure can generate one passband and can generate a transmission zero point at the same time; the complementary opening resonance ring defect ground structure and the microstrip lines can generate one passband by coupling, can generate one transmission zero point at the same time and are cascaded to form the dual-band filter. According to the filter, two transmission zero points are introduced, so the out-of-band rejection is improved, the passband selectivity is improved, and the external quality factor is improved by adopting a conical gradual feeding mode.

An integrated balanced-filter which acts as a matching network, a balun and an extracted-pole bandpass filter is disclosed. The balanced-filter includes an unbalanced terminal, a first balanced terminal and a second balanced terminal, a first resonator connected to the unbalanced terminal, a second resonator connected to the first balanced terminal, and a third resonator connected to the second balanced terminal. The second resonator is positively coupled to the first resonator, and the third resonator is negatively coupled to the first resonator, which provides a balun function and a bandpass-filtering function. The balanced-filter further includes extracted-pole notch filters, which can introduce a transmission zero and implement matching network. The balanced-filter can be implemented in a multi-layered substrate, thereby reducing the size of the balanced-filter.

The invention discloses a direct and integrated design method of band-pass filters. In order to overcome the defect that the coupling matrix derived from the traditional integrated design method of the generalized Chebyshev single-pass-band or multi-pass-band band-pass filters is only narrow-band approximation and can not be used for integrated band-pass filters, the method is available for integrating the generalized Chebyshev single-pass-band or multi-pass-band band-pass filters in a band-pass domain directly, and improving the group delay characteristic in the pass band of the filter by introducing a plurality of transmission zeros. The direct and integrated design method can be used for extracting a network matrix of the generalized Chebyshev band-pass filters of the transmission zeros which have any bandwidth and are positioned at any frequency; and the derived network matrix has practical physical significance, while the network matrix derived from the traditional scheme can be taken as a low-pass narrow-band approximation result of the network matrix derived by using the method disclosed by the invention. The whole method disclosed by the invention has the advantages of simpleness, fastness and accuracy.

The invention discloses an L-band miniature low-pass filter. The low-pass filter has two transmission zeros, the prototype is a fifth-order Chebyshev low-pass filter, an equivalent lumped parameter element is implemented by means of an LTCC (low-temperature co-fired ceramic) multilayered structure, and the L-band miniature low-pass filter comprises two stages of parallel resonant units, three stages of parallel ground capacitors, an input port and an output port; under the same technical index condition, the size of the filter is greatly reduced, and out-of-band harmonics are effectively suppressed. The L-band miniature low-pass filter has the advantages of small size, light weight, high integration degree, little in-passband insertion loss, good standing waves, good high-end suppression, high temperature stability, high consistency in the electrical property indexes of batches, low mass production cost and the like, and is applicable to corresponding communication systems having rigorous requirements on size, weight, performance and reliability, such as radio frequency transceiving front ends.

The invention discloses a double-layer substrate integrated waveguide-based balanced dual-mode band-pass filter; the balanced dual-mode band-pass filter comprises an upper surface metal layer, a firstdielectric substrate, a middle metal layer, a second dielectric substrate and a lower surface metal layer which are sequentially and coaxially arranged from top to bottom. Two sets of feed ports arearranged in the upper surface metal layer and the lower surface metal layer separately; a plurality of metal through holes and two micro-disturbance metal through holes are formed in the first dielectric substrate and the second dielectric substrate; and a rectangular metal gap is formed in the center of the middle metal layer. According to the filter, the characteristics of the PEC-PMC are utilized, and the rectangular metal gap is etched in the middle metal layer, so that the characteristic of high common mode rejection in a wide frequency band is achieved; and the coupling between the dualmodes in a substrate integrated waveguide rectangular cavity, and a non-resonant node introduced between a source and a load are utilized, so that a controllable transmission zero point and a high-performance balance filter with the high common mode rejection in the wide frequency band are generated on the two sides of a differential mode passband, the selectivity and the common mode rejection performance of the balance filter are effectively improved, and the actual requirements of a differential communication system are met.

An embedded resonator sharpens the frequency characteristics of a coaxial low pass filter. The resonator introduces finite transmission zeros to the response of the low pass filter, thereby suppressing spurious modes occurring just above the operating frequency. Two parameters are used to tune the operation of the embedded resonator. The length of an insert into the filter's transmission line substantially controls the resonant frequency, and the gap width substantially controls the coupling of the embedded resonator to the low pass filter.

The invention provides an ultra-wide-band filter with high selectivity and an ultrahigh attenuation band restrain effect, which is composed of a first input/output port, a second input/output port, an interlayer medium substrate, an upper layer micro-strip structure arranged on the interlayer medium substrate and an underlying metal floor board. The upper layer micro-strip structure comprises a first feed network, a multi branch knot loading multimode resonator and a second feed network. The multi branch knot loading multimode resonator of the upper layer micro-strip structure has five resonance modes in an ultra-wide-band frequency band scope, a transmission zero is generated above and below a passband respectively, and passband selectivity is greatly improved. In addition, generated zero and frequency doubling zero of the zero restrains high sequence resonance modes of the multimode resonator, and restraining effects of an upper attenuation band of the passband are greatly broadened. The ultra-wide-band filter has good passband character, high passband selectivity and ultra-high attenuation band restraining effect, and is applicable to ultra-wide-band wireless communication systems with high standard communication.

The invention discloses a cavity filter. The cavity filer comprises a metal cavity and a metal cover plate which is positioned on the metal cavity, wherein the metal cavity comprises at least eight resonance cavities which are coupled in sequence; a resonance rod is arranged in each resonance cavity; and the resonance rods in the first and the last resonance cavities are connected with an input signal connector and an output signal connector respectively. The coupling between the adjacent resonance cavities is magnetic coupling; coupling windows and coupling rods are arranged between the corresponding resonance cavities on the left and right sides of a passband; four places of crossed coupling is introduced, so that two transmission zero points can be generated on the left and right sides of the passband respectively, and higher out-of-band rejection can be achieved; the outline dimension of the overall filter cavity is not changed; the order of the filter is not increased, and the size of the filter is not enlarged; meanwhile, the cavity filter is easy to process and debug, and low in cost; and the large-batch production of the cavity filter can be achieved.