273 results about "Balun" patented technology

The invention discloses a biconical antenna balun equivalent circuit modeling optimization method based on a multi-conductor transmission line, and belongs to the technical field of electromagnetic simulation. The method comprises the following steps: firstly, establishing a three-dimensional electromagnetic model of a biconical antenna balun based on a finite element method, and setting ports and defining boundary conditions in combination with an actual current transmission path; then, distribution parameters among conductors are extracted through a multi-conductor transmission line theory, and a Balun circuit topological structure is constructed; and finally, taking the antenna coefficient as an optimization target, carrying out iterative optimization on equivalent circuit element parameters by adopting a multi-target genetic algorithm, considering a plurality of optimization targets in a broadband range, and finally obtaining a high-precision equivalent circuit model. Through combination of electromagnetic simulation and an intelligent optimization algorithm, high-efficiency extraction of complex Balun structure distribution parameters and adaptive optimization of circuit parameters are realized, and the simulation precision of the biconical antenna is remarkably improved.

The utility model discloses a balun-integrated full-wave oscillator radiation unit, and aims to solve the problems that a low-frequency bowl-shaped oscillator and a high-frequency die-cast half-wave oscillator are used in the conventional high-low frequency nesting scheme, so that the requirements of miniaturization and light weight of an antenna are difficult to meet, the processing cost is extremely high, and the cost is low. And meanwhile, the high-frequency oscillator is arranged in the bowl-shaped oscillator, so that the horizontal plane wave width deformation of the high-frequency oscillator is caused, the gain is influenced, and the market demand cannot be met. The Balun-integrated full-wave oscillator radiation unit comprises a fixed support and a PCB radiation plate installed on the fixed support. The structure of the full-wave oscillator is relatively simple, assembly can be completed only by installing the single-balun integrated feed sheet in the fixing support and welding and fixing the single-balun integrated feed sheet and the PCB radiation plate, miniaturization design can be achieved through the microstrip technology, the printed circuit technology and the like due to the fact that single-face embedded coupling is adopted, the requirement of miniaturization equipment is met, machining is easy, and cost is low. The production efficiency can be greatly improved, and the production cost is reduced.

An electronic device may include wireless circuitry having an oscillator. The oscillator can include a first transistor having a source-drain terminal coupled to a tail node, a second transistor having a source-drain terminal coupled to the tail node, a first coil having a first terminal coupled to the tail node and having a second terminal coupled to a power supply line, and a second coil inductively coupled to the first coil. The first and second coils can be part of a balun. The balun can be coupled to a tunable capacitance. The tunable capacitance can include multiple differential switchable capacitor circuits. The balun and the tunable capacitance can form a balun phase noise filter configured to reduce a phase noise associated with the oscillator.

The invention discloses a double-frequency circularly polarized antenna element, which belongs to the technical field of antennas and comprises a high-frequency-band radiation unit and a low-frequency-band radiation unit. The high-frequency band radiation unit comprises a first dielectric substrate and a first feed probe. A first radiation patch is embedded in one end face of the first dielectric substrate, and the first radiation patch is provided with two symmetrical chamfers. The top end of the first feed probe passes through the first through hole and is fixedly connected with the first radiation patch. The low-frequency-band radiation unit comprises a second dielectric substrate, a second radiation patch and a third dielectric substrate. The second radiation patch is arranged on the second dielectric substrate. The second dielectric substrate is provided with a second metalized through hole. The third dielectric substrate is provided with a Chebyshev Balun feed printed line. The antenna element provided by the invention not only can realize the circular polarization of the antenna, but also can reduce the coupling between antennas of different working frequency bands while expanding the bandwidth of the antenna, improve the isolation between two working frequency band ports, and reduce the cross polarization.

Ultra-Wideband (UWB) technology is a wireless technology supporting the transmission of large amounts of digital data over short distances using coded impulses over a wide frequency spectrum with very low power. Enhanced link performance and functionality of such UWB systems is presented exploiting multiple directive antennas for spatially filtering undesired signals and increasing signal strength whilst circuit complexity is reduced by eliminating baluns in prior art solutions. Further enhancements support payloads with flexible encoding schemes, improved channel utilization, reduced processing logic, improved robustness in correlation techniques, versatile synchronisation techniques, improved ranging, as well as providing for improved inter-symbol interference tolerance and detection.

The invention discloses a Terahertz broadband high-gain Vivaldi antenna based on a CPW (Coherent Plane Waveguide) rotary slot line structure, and belongs to the field of Terahertz communication. The antenna adopts an integrated single-layer metal structure on the top layer of a dielectric substrate, and is divided into a radiation arm and a CPW rotating slot line balun along the axial direction. The inner side edge of the radiation arm is a smooth exponential change curve, and the middle exponential gradual change groove forms a broadband traveling wave radiation channel. Periodic grid choke grooves are loaded on the outer side edge so as to suppress edge surface waves and improve a directional diagram. The feed part adopts a CPW to slot line balun structure to realize conversion from an unbalanced mode to a balanced mode, and a fan-shaped radial branch knot is utilized to form a broadband virtual short circuit boundary at a feed point to ensure unidirectional efficient transmission of energy. In addition, a group of string-shaped director patches are arranged in the opening area of the exponential gradual change groove along the central axis, and the wave beam is guided through phase correction. The terahertz planar antenna effectively solves the problems of limited bandwidth and insufficient gain of the terahertz planar antenna, and has the characteristics of compact structure, easiness in integration, excellent radiation performance and the like.

The invention discloses a wide-beam omnidirectional circularly polarized antenna and a radio communication system comprising the same, and belongs to the technical field of linear communication antennae, the wide-beam omnidirectional circularly polarized antenna comprises a feed connector, a printed board feed balun, a conical hollow substrate, a feed printed board and a radiation printed patch; by adopting the split type conical substrate which is composed of the feed printed board at the top and the conical hollow substrate, connection and conduction of the feed printed board and other structures are facilitated, and the process cost is reduced while the process credibility is enhanced; the feed form of the antenna is set to be printed board balun feed, the microstrip line extending according to a certain curvilinear equation is arranged on the copper layer of the printed board balun, and the printed board feed balun is connected and conducted with the spiral radiation printed patch through the feed printed board, so that the performance requirements of low axial ratio and high gain of the antenna can be ensured, and the antenna can be widely applied to the field of antenna devices. And the technical requirements of wide wave beams can be met.

The invention provides a gain-reconfigurable active phase shifter with a low phase error, and relates to the technical field of phase shifters, and the phase shifter comprises a quadrature coupler which converts a radio frequency input signal into a shunt radio frequency signal; the input matching Balun converts the shunt radio frequency signal into a shunt differential signal; the digital control signal received by the phase inversion variable gain amplifier is used for controlling the on-off state of a differential pair in each differential group, and determining a differential combination current corresponding to a differential pair combination in a conduction state based on a shunt differential signal corresponding to each differential pair; the differential combination current is used for representing a gain state corresponding to the differential pair combination; the input impedance and the output impedance of the phase inversion variable gain amplifier in different gain states are kept unchanged; the vector synthesis module determines a phase shift differential signal based on the differential combined current; the output matching Balun converts the phase shift differential signal into a radio frequency output signal. The antenna has a wide gain adjustable range and a low phase error.

The invention discloses a low-mismatch ultra-wideband active balun, which belongs to the technical field of analog integrated circuits and comprises a first-stage amplifier and a second-stage amplifier which are sequentially arranged. The first-stage amplifier adopts a differential structure, and finally conversion from a single-end signal to a constant-amplitude and anti-phase differential signal is achieved. The second-stage amplifier isolates the influence of a rear-stage load on a front stage, and the symmetry of differential signals is ensured. In the second-stage amplifier, a seventh NMOS transistor and a tenth NMOS transistor form positive feedback; by introducing the cross coupling capacitor, the gate-source voltage difference between the eighth NMOS transistor and the ninth NMOS transistor is increased, voltage recovery is formed, compared with a traditional active balun, the second-stage amplifier reduces phase and amplitude mismatch of an output signal through positive feedback, meanwhile, the bandwidth is expanded, and therefore the bandwidth is increased. And the grid source signal amplitude is increased by utilizing source electrode voltage recovery, the equivalent transconductance is enhanced, and the phase and amplitude of the output signal are further stabilized.

A method, phase shifter, and user equipment (UE) for transmitting and receiving signals in a phased array are disclosed. The method includes receiving a transmit single-ended input signal on a single-ended side of a balun of the phase shifter and generating a transmit differential input signal on a differential side of the balun through the balun; generating a transmit in-phase signal and a transmit quadrature signal based on the transmit differential input signal through a differential quadrature coupler of the phase shifter; and combining the transmit in-phase signal and the transmit quadrature signal into a differential phase-shifted output signal through a differential attenuator of the phase shifter.

The invention discloses a small broadband cavity-backed radiator, which belongs to the technical field of electromagnetic fields and microwaves and comprises a reflection cavity, a loading medium, a printed balun, a printed oscillator, a low-density medium support and double leads. The low-density medium support is used for supporting the printed oscillator; the printed balun and the printed oscillator are electrically connected through double leads; the loading medium is used for adjusting the impedance frequency characteristic of the printed oscillator in the reflection cavity; the printed Balun adopts a strip line-flat plate line-parallel double-line structure and is used for realizing unbalanced-balanced transmission mode conversion and impedance conversion of 3: 1 bandwidth; and the printed oscillator is used for radiating electromagnetic energy and is matched with the multi-ring-groove loading medium and the printed Balun to realize impedance-frequency characteristic balance within a 3: 1 bandwidth range. The small broadband back cavity radiator can effectively solve the problems that in the prior art, the caliber of a reflection cavity of a traditional broadband back cavity radiator is large, the loading effect is not ideal when the bandwidth of a directional diagram is 4 GHz or above, and directional diagram distortion occurs.

In an embodiment, a circuit includes a first input terminal configured to be coupled to a first terminal of a first capacitor, a second input terminal configured to be coupled to a second terminal of the first capacitor, a balun including a primary inductor and a secondary inductor, and a second capacitor. The primary inductor includes a first terminal coupled to the first input terminal, a second terminal coupled to the second input terminal, a first inductive portion coupled between the first terminal of the primary inductor and a first intermediate terminal, a second inductive portion coupled between the second terminal of the primary inductor and a second intermediate terminal, and a third inductive portion coupled between the first and second intermediate terminals. The secondary inductor includes a first terminal coupled to a ground terminal. The second capacitor is coupled between the first and second intermediate terminals.

The invention discloses a lumped element and acoustic resonator mixed filtering balun and radio frequency front end system, which comprises a first module, a second module, a third module, a fourth module, a fifth module, a sixth module and a seventh module, and is characterized in that the first module, the third module and the fourth module are acoustic-electric mixed modules and comprise lumped elements and acoustic resonators; the first module, the fifth module, the sixth module and the seventh module are used for forming a plurality of transmission zero points outside a passband of the filtering balun so as to enhance the selectivity and out-of-band rejection of the edge of the passband, and the second module, the fifth module, the sixth module and the seventh module are electric modules, are formed by lumped elements and are used for realizing the passband of the required filtering balun. Reflection loss caused by impedance mismatching when discrete devices are cascaded can be avoided, insertion loss of a system is remarkably reduced, the size and cost of the system are reduced, the broadband advantage of an electrical filter and the high selectivity advantage of an acoustic filter are integrated, and meanwhile the high-performance filtering balun which is miniaturized, large in bandwidth and high in selectivity is achieved.

The invention discloses a multi-frequency antenna radiation unit device with a decoupling function, and belongs to the field of mobile communication antennas. The high-frequency radiation unit comprises a balun electrically connected with the reflecting plate and a radiation arm connected to the balun; the low-frequency radiation unit is positioned on the periphery of the high-frequency radiation unit and is arranged on the reflecting plate; the capacitor loading assembly comprises a coupling patch connected with the radiation arm and a capacitor branch connected to the balun, the capacitor branch is located on the side, close to the reflecting plate, of the balun, the coupling patch and the capacitor branch form an additional capacitor connected with the high-frequency radiation unit in parallel, and the total equivalent capacitance of the high-frequency radiation unit is changed through the additional capacitor; therefore, the resonant frequency of the high-frequency radiation unit is shifted out of the low-frequency working frequency band, common-mode resonance generated when the high-frequency radiation unit and the low-frequency radiation unit are adjacently arranged is eliminated, the standing-wave ratio of a low-frequency port is improved, the working bandwidth is widened, distortion of a low-frequency radiation pattern is eliminated, and the coverage quality of a base station is guaranteed.

The invention provides a working mode reconfigurable power division chip circuit structure and a working method thereof. The circuit structure comprises an input port tap, two output port taps, a three-wire coupling spiral coil, a grounding pole and two control switches. One input port tap is connected with a middle coil of the three-wire coupling spiral coil to serve as an incident signal input port; the two output port taps are connected with two ends of an outer side coil of the three-wire coupling spiral coil to serve as output signal output ports; the two ends of the grounding pole are connected between the tail ends of the middle coils of the three-wire coupling spiral coils through the control switches respectively. The two control switches are used for switching the working mode of the working mode reconfigurable power division chip circuit structure. According to the power divider, the connection state of the three-wire coupling spiral coil and the grounding pole is changed by switching the on-off state of the control switch, switching of two working modes of power division and balun is achieved in the same compact circuit structure, and efficient utilization of the chip size is achieved.

The utility model discloses a radio frequency front-end module and electronic equipment. The radio frequency front-end module comprises a substrate, a power amplifier and a balun, the substrate is provided with a grounding metal layer, and the power amplifier comprises a first output end and a second output end. The balun comprises a capacitor, a primary coil and a secondary coil, the primary coil and the secondary coil are coupled, the primary coil and the secondary coil are wound on the substrate, and the primary coil is connected between the first output end and the second output end; one end of the capacitor is connected to the midpoint of the primary coil, and the other end of the capacitor is connected to the grounding metal layer through a plurality of metal via holes. When the capacitor is grounded, the technical scheme that the plurality of metal via holes are connected with the grounding metal layer is adopted, so that even if the radio frequency front-end module is applied to electronic equipment with a relatively poor grounding environment, the plurality of metal via holes can form a backflow path through good grounding of the metal via holes; the condition of harmonic deterioration caused by crosstalk of harmonic signals can be reduced or even avoided, and the transmission quality of radio frequency signals is improved.

An ultra wide band (UWB) antenna formed from a single piece of material includes: a planar portion arranged above a ground plane; an aperture through the planar portion; a ground connecting portion formed from cutting of the aperture and configured to electrically connect the UWB antenna to the ground plane; and a tapered portion configured to be electrically connected to a feed, the tapered portion extending around at least 40 percent of a periphery of the planar portion and extending from the planar portion toward the ground plane, where a height of the tapered portion decreases around the periphery of the planar portion moving away from the feed, and where a lower edge of the tapered portion is spaced from the ground plane by a gap.

The embodiment of the present application provides a kind of single-layer planar dipole antenna, wherein the antenna is applied to intelligent vehicle technical field, wherein the single-layer planar dipole antenna includes: base material, planar dipole antenna, planar balun, differential double-wire transmission line and band ground coplanar waveguide;Wherein, planar dipole antenna, planar balun, differential double-wire transmission line and band ground coplanar waveguide are arranged on the same layer of base material surface;Band ground coplanar waveguide includes center signal conductor and left and right two side reference ground, two metal arms of planar balun are connected to left and right two side reference ground of band ground coplanar waveguide respectively, and the upper end of differential double-wire transmission line is respectively connected to two radiation arms of planar dipole antenna, while the lower end of differential double-wire transmission line two transmission lines are respectively connected to one of center signal conductor and left and right two side reference ground of band ground coplanar waveguide.The embodiment of the present application can realize the integrated molding of antenna by the structure of single surface arrangement antenna, and reduce the integration difficulty of antenna.

The invention discloses a system-integrated dipole antenna and a manufacturing method thereof, and relates to the technical field of antenna design, and the system-integrated dipole antenna comprises a dipole radiation module which is used for achieving the energy conversion between a radio frequency signal and a space electromagnetic wave; an integrated balun module and a transceiver circuit module are arranged on the circuit board; the integrated balun module is connected with the two metal radiation arms of the dipole radiation module through feeding points. The transmit-receive circuit module is electrically connected with the integrated Balun module, and performs signal transmission with the dipole radiation module through the integrated Balun module. Compared with a traditional separated antenna and a system architecture of a radio frequency front end, the system integrated dipole antenna realizes balance feed and differential interface integration, energy loss and the size of the system integrated dipole antenna are remarkably reduced, and the integration level and reliability of the system integrated dipole antenna are remarkably improved.

This invention relates to the field of electromagnetic fields and microwave technology, aiming to solve the problems of traditional orthogonal short-circuit dual-wire baluns, which suffer from strong jumper inductance effects, large dual-wire radiation, and severe pattern distortion above 5GHz. The planar orthogonal differential feed network also suffers from high network losses and manufacturing costs, making it unsuitable for widespread use in electronic devices above 5GHz. The invention provides a dual-polarized back-cavity radiator, including a reflective cavity enclosure component forming an inner reflective cavity and a ring reflective cavity. An orthogonal printed composite oscillator is disposed within the inner reflective cavity, comprising horizontal and vertical printed composite oscillators, with oscillator plates connected to both sides of each oscillator. Each printed composite oscillator integrates a dual-wire balun, impedance compensation lines, and open-circuit compensation sections. Each printed composite oscillator includes a printed oscillator with front, back, and mezzanine circuits. The impedance compensation lines and open-circuit compensation sections are embedded within the printed oscillator and connected to the mezzanine circuits. The dual-wire balun includes parallel dual wires connected to the front and back circuits.

The application provides a high-balance active balun circuit, which comprises an RF signal input port, a signal input matching stage, a single-end to differential circuit and an output load stage, wherein the signal input matching stage comprises a first transistor, a second transistor, an input resistor and an input inductor, and the single-end to differential circuit comprises a third transistor, a fourth transistor, a fifth transistor and a capacitor. The application does not need to waste chip area to make a complex matching circuit. When the circuit is connected in the front stage, the circuit will not cause the problem that power cannot be transmitted due to high-frequency reflection. The phase adjusting inductor is introduced into the circuit, and the frequency phase characteristics of the inductor are used to compensate the phase imbalance of the differential output. The bandwidth extension technology is used in the load, so that the phase shifter maintains the flatness of the gain in a wide frequency. Meanwhile, the two-stage cascade transistor is used to realize the single-end input to differential output gain stage architecture, which is more suitable for low-voltage application.

This invention discloses an integrated antenna assembly and antenna. The integrated antenna assembly includes a phase shifter and a radiating element. The phase shifter includes a shielding housing, a feed network assembly, and a main feed line. One side of the shielding housing serves as a reflective surface, and the other side is divided into a main receiving cavity and a secondary receiving cavity. The feed network assembly is disposed within the main receiving cavity, and the main feed line is disposed within the secondary receiving cavity and electrically connected to the feed network assembly. The radiating element includes a radiator and a balun assembly. The radiator is disposed on the reflective surface, and one end of the balun assembly is electrically connected to the radiator, while the other end extends into the main receiving cavity and is electrically connected to the feed network assembly. By concentrating the feed network assembly, the main feed line, and the radiating element onto the shielding housing, the number of coaxial cable connections can be reduced, resulting in simpler assembly and fewer connection positions. This achieves integration and modularity of the radiating array and the phase shifter, reducing performance loss.

The application discloses an ultra-wideband odd harmonic frequency mixer for frequency spreading, and belongs to the technical field of planar harmonic frequency mixing, and comprises a first microstrip line, a Marchand balun, a first Schottky diode, a second Schottky diode, a matching circuit and a second microstrip line; the first microstrip line is located at a radio frequency input end and is connected with a non-balanced end of the Marchand balun, two balanced ends A and B of the Marchand balun are respectively connected with an anode of the first Schottky diode and a cathode of the second Schottky diode, the cathode of the first Schottky diode and the anode of the second Schottky diode are connected in sequence and are connected with the matching circuit and the second microstrip line in sequence, and the second microstrip line is connected with a local oscillator / intermediate frequency port. The harmonic frequency mixer can be directly used for frequency expansion of an existing mainstream frequency spectrometer, and the expansion range can cover the bandwidth of two to three standard waveguide frequency bands.

The ultra wide band (UWB) technology is a wireless technology that transmits large amounts of digital data over a wide spectrum over a short distance at very low power. However, in order to support their deployment in a wide range of applications, it is beneficial to provide a solution in which a plurality of directional antennas directed in different directions are utilized to ensure spatial filtering of undesired signals and increase signal strength; improving link quality of service with a dynamic configuration of a multi-pulse beam for transmitting bits / symbols within a packet; dynamic configuration of one or more frequency bands operating with the transmitter; and an antenna subsystem for providing an omnidirectional radiation pattern is utilized, filtering and balun functions are provided, the size is small, and the cost is low.

A balun is enhanced with design features that extend the operational bandwidth of the balun allowing the balun to operate at lower frequencies. The design enhancements also suppress resonances that otherwise cause sudden power drops at a resonance frequency while a load is connected between the balun's differential outputs.

The application discloses a modular high-gain circularly polarized Vivaldi array antenna, which comprises edge antennas, middle antennas and a mounting base; the mounting base comprises a square metal plate printed with a feeding layer, four edge antennas and / or middle antennas are inserted into the square metal plate, and two edge antennas and / or middle antennas form an X-direction plane and a Y-direction plane perpendicular to each other, and a feeding seat is arranged in the center of the square metal plate; the edge antennas and the middle antennas are in a sheet structure and are composed of a bottom insertion structure and a top antenna structure, the bottom insertion structure comprises an insertion column and a wiring passage; a feeding balun is connected to a feeding source, and then the edge antennas and / or middle antennas in the same plane are connected to each other through the wiring passage to form Vivaldi antennas; the mounting base arrays are arranged to mount the antennas to form a Vivaldi array antenna, and the edge antennas are all edge antennas, and the other antennas are all middle antennas. The application can realize a modular circularly polarized Vivaldi array antenna, has a compact structure, and has strong antenna gain and expansibility.

The application discloses a kind of low mismatch ultra-wideband active balun, analog integrated circuit technical field, comprising: first-stage amplifier and second-stage amplifier arranged in sequence.The first-stage amplifier adopts differential structure, and finally realizes the conversion of single-ended signal to equal-amplitude differential signal.The second-stage amplifier isolates the influence of subsequent stage load on previous stage, and ensures the symmetry of differential signal.In the second-stage amplifier, seventh NMOS transistor and tenth NMOS transistor form positive feedback;by introducing cross-coupled capacitor, the gate-source voltage difference of eighth NMOS transistor and ninth NMOS transistor is increased, voltage recovery is formed, compared with traditional active balun, the second-stage amplifier of the application reduces the phase and amplitude mismatch of output signal by positive feedback at the same time, expands bandwidth, increases gate-source signal amplitude by using source voltage recovery, enhances equivalent transconductance, and further stabilizes the phase and amplitude of output signal.

The embodiment of the application provides a kind of passive mixer and antenna.Belongs to communication technical field.The passive mixer includes: multi-branch microstrip line balun, mixing diode and output balun module;The first input end of multi-branch microstrip balun is the first input end of passive mixer, the second input end of multi-branch microstrip line balun is the second input end of passive mixer, the first output end of multi-branch microstrip line balun is connected with the first input end of mixing diode, the second output end of multi-branch microstrip line balun is connected with the second input end of mixing diode, the first output end of mixing diode is connected with the first input end of output balun module, the second output end of mixing diode is connected with the second input end of output balun module, and the output end of output balun module is the output end of passive mixer.The method solves the problem of high cost of active mixer transformation and poor output signal quality of passive mixer.

Apparatus and methods for radio frequency (RF) amplification are disclosed. In certain embodiments, an RF amplifier includes an output node configured to output an RF output signal, a main amplifier stage including a differential output, a first differential balun combiner configured to provide a first single-ended RF signal to the output node based on combining a first differential RF signal from the differential output of the main amplifier stage, an auxiliary amplifier stage including a differential output, a transformer component, and a second differential balun combiner configured to generate a second single-ended RF signal based on combining a second differential RF signal from the differential output of the auxiliary amplifier stage. The second differential balun combiner provides the second single-ended RF signal to the output node through the transformer component.

The invention discloses an on-chip passive transformer Balun with broadband and low phase noise, and belongs to the field of integrated circuit chip design. The invention comprises two primary coils, two secondary coils and a ground plane. The primary coil and the secondary coil are mutually nested to improve the coupling coefficient. The broadband low-phase noise on-chip passive transformer Balun can be used for occasions where differential-single-ended signal conversion or single-ended-differential signal conversion needs to be completed in integrated circuit design, for example, the broadband low-phase noise on-chip passive transformer Balun can work in the frequency band of 4 GHz-23 GHz, and differential signals with the phase difference of 180 degrees output by a double mixer in an IQ modulator module are converted into single-ended signals. The on-chip transformer balun is large in coupling coefficient and small in energy loss, and therefore low phase noise of signals is guaranteed.