Abstract: A WTRU may perform cERFs. A method may include any of: transmitting, to a nEAR, a signal requesting an IP address identifying (e.g., associated with) a DNS server associated with the WTRU; applying, by the WTRU, any of EI record rules for the identified DNS server, or updating EI records with the IP address identifying the DNS server; transmitting, to a DNS server, a DNS query associated with a FQDN; receiving, in response to the DNS query, FQDN resolution from the DNS server; on condition that a mobility event of the WTRU occurs, transmitting, to the nEAR, a signal requesting information for updating the EI records of the WTRU; and applying, by the WTRU, any of the updated EI record rules in order to perform any of: (1) redirecting application session traffic to provides session continuity for the WTRU, and (2) breaking any number of application sessions.

Abstract: A signal transmission device includes a signal side electrode; a first signal line connected to one side of the signal side electrode; a second signal line connected to the other side of the signal side electrode; a power source side electrode that forms a pair with the signal side electrode and is connected to the signal side electrode via an electronic component including at least an inductor component; and a capacitive coupling part that capacitively couples the power source side electrode to a ground wiring or a power source wiring. The first signal line, the signal side electrode, and the second signal line form a transmission path for transmitting an electric signal. The first signal line and the second signal line transmit power via the signal side electrode, the electronic component, and the power source side electrode.

Abstract: The present disclosure relates to a waveguide section (101) comprising at least one air-filled waveguide conducting tube (104; 104a, 104b, 104c, 104d) having a longitudinal extension (L1). Each waveguide conducting tube (104; 104a, 104b, 104c, 104d) has an electrically conducting inner wall (106) and comprises at least one set of at least two electrically conducting integrally formed protrusions (107; 107a, 107b, 107c, 107d). Each protrusion (107a, 107b, 107c, 107d) is electrically conducting and comprises a corresponding plate part (109; 109a, 109b, 109c, 109d) that is adapted to form a capacitance (C1, C2, C3, C4; C10; C11) with at least one other plate part in the same set of protrusions (107; 107a, 107b, 107c, 107d) for each set of protrusions (107; 107a, 107b, 107c, 107d), whereby an RF, radio frequency, signal passing via a corresponding waveguide conducting tube (104) is arranged to be electromagnetically filtered.

Abstract: The present disclosure provides a dual-polarized antenna, which is advantageous for a reduction in size by significantly reducing the complexity of a structure while satisfying a Cross Polarization ratio (CPR) characteristic and an isolation characteristic, that is, advantages of a dual feed, by enabling a dual feed using a shift series feed even without another structure in one antenna structure.

Abstract: A diversity antenna for receiving radio frequency (RF) signals includes a horizontally-polarized antenna element coupled to a vertically-polarized antenna element in a fixed orthogonal relationship. The vertically-polarized antenna element is a blade antenna which includes a vertically-oriented printed circuit board (PCB) on which is disposed a pair of conductive strips. The horizontally-polarized antenna element includes two loop antennas which are arranged and conductively coupled in parallel. Each loop antenna includes a horizontally-oriented, disc-shaped PCB on which is disposed a pair of conductive loops. To facilitate the orthogonal coupling between the pair of antenna elements, each disc-shaped PCB includes a central slot dimensioned to receive the vertically-oriented PCB.

Abstract: A microstrip ultra-wideband antenna is provided, including: an upper dielectric substrate, a radiation patch, an open-circuit line, a short-circuit line, a ground plane, a lower dielectric substrate, a vertical dielectric substrate, isolation walls, a hyperbolic microstrip balun feeder and an ideal wave port. The radiation patch is attached to a lower surface of the upper dielectric substrate; the ground plane is attached to an upper surface of the lower dielectric substrate; the short-circuit line and the open-circuit line are attached to a rear surface and a front surface of the vertical dielectric substrate respectively; the hyperbolic microstrip balun feeder is attached to the front and rear surface of the vertical dielectric substrate; the isolation walls are located between the upper dielectric substrate and the lower dielectric substrate perpendicularly to an end of the radiation patch; and the ideal wave port is provided below the hyperbolic microstrip balun feeder.

Abstract: The present disclosure provides a method for long range communication through underwater and underground environments by converting encoded message data into spherical coordinates and rotating a magnet about axes of rotation corresponding to those spherical coordinates at a transmitter. A receiver configured to detect the magnetic dipole field of the generated electromagnetic wave can thus determine the orientation of the magnetic dipole, deduce the spherical coordinates, and decipher the encoded data. A system comprising a mechanical antenna transmitter and receiver with a magnetic field sensor arrangement for carrying out the method is also provided.

Abstract: Various avionics systems may benefit from appropriate integration of distance measurement equipment, traffic collision avoidance systems, and transponders, with the distance measurement equipment using a dedicated antenna. A system can include a transponder processor. The system can also include a top antenna receiver configured to connect to a top antenna. The transponder processor can be configured to communicate using the top antenna. The system can also include a bottom antenna receiver configured to connect to a first bottom antenna, wherein the transponder processor is configured to communicate using the first bottom antenna. The system can further include a distance measure equipment processor integrated with the transponder processor and configured to measure distance using a second bottom antenna.

Abstract: A compact radiofrequency driver includes at least one axial port intended to be connected to a radiating antenna, at least one output intended to collect received signals and at least one input intended to transmit signals, comprising first and second septum polarizers and a frequency filter, the second polarizer being connected, via its common port, to a first rectangular port of the first polarizer and the frequency filter being connected to the second rectangular port of the first polarizer and being configured to filter a reception or transmission frequency band, these two bands being different, and wherein at least one of the polarizers is configured to convert a circularly polarized signal received on said axial port of the driver into a linearly polarized signal in a reception frequency band and in that at least a second polarizer is configured to convert a linearly polarized signal transmitted to the driver by the input into a circularly polarized signal in a transmission frequency band.

Abstract: High power radio frequency (RF) switches with low leakage current and low insertion loss are provided. In one embodiment, an RF switch includes a plurality of terminals including an antenna terminal, a receive terminal, and a transmit terminal. The RF switch also includes a plurality of transistors that are controllable to set the RF switch in a first mode or a second mode, and an inductor electrically connected between the antenna terminal and the receive terminal.

Abstract: An acoustic wave device includes a piezoelectric substrate, an IDT electrode provided on the piezoelectric substrate, a support provided on the piezoelectric substrate so as to surround the IDT electrode, and a cover provided on the support. The support has a larger thermal expansion coefficient than the piezoelectric substrate. The IDT electrode is provided in a hollow space that is surrounded by the piezoelectric substrate, the support, and the cover. The support includes an inner surface on a side of the hollow space, and an outer surface on a side opposite to the inner surface, and the support includes a recess provided in at least one of the inner and outer surfaces.

Abstract: An array antenna has a plurality of antenna unit cells arranged in rows and columns, or in another configuration. Each unit cell from the plurality of unit cells includes a circularly polarized radiator and a balun. The array antenna further includes a reactive element or a circuit element (such as a capacitor or resistor or even an inductor) on the circularly polarized radiator that is coupled an adjacent unit cell in one of the row and the column. A spacing distance between adjacent unit cells coupled via the circuit element that is at most half of a wavelength at a frequency maximum of the array antenna, wherein the spacing distance reduces likelihood of grating lobes.

Abstract: An acoustic wave element of the present disclosures has a piezoelectric substrate and an acoustic wave resonator on a main surface of the piezoelectric substrate. The acoustic wave resonator is one being divided into a first IDT electrode and a second IDT electrode which are electrically connected to the first IDT electrode. The first IDT electrode includes a first comb-shaped electrode on the signal input side and a second comb-shaped electrode on the signal output side. The second IDT electrode includes a third comb-shaped electrode on the signal input side and a fourth comb-shaped electrode on the signal output side. The direction of arrangement of the third comb-shaped electrode and the fourth comb-shaped electrode from the third comb-shaped electrode toward the fourth comb-shaped electrode is different from the direction of arrangement from the first comb-shaped electrode toward the second comb-shaped electrode.

Abstract: The invention relates to a method for automatically adjusting a multiple-input-port and multiple-output-port tuning unit, for instance a multiple-input-port and multiple-output-port tuning unit coupled to the antennas of a radio transceiver using a plurality of antennas simultaneously. An automatic tuning system using this method has 4 user ports and 4 target ports, and comprises: 4 sensing units; a signal processing unit, the signal processing unit estimating real quantities depending on an impedance matrix seen by the target ports, using sensing unit output signals, the signal processing unit delivering a tuning instruction; a multiple-input-port and multiple-output-port tuning unit comprising adjustable impedance devices; and a tuning control unit receiving the tuning instruction and delivering tuning control signals to the multiple-input-port and multiple-output-port tuning unit, the reactance of each of the adjustable impedance devices being mainly determined by one or more of the tuning control signals.

Abstract: An active distributed antenna system and a relay unit thereof are disclosed.

Abstract: The disclosure discloses a dual-mode terminal antenna, comprising a main antenna comprising a main antenna of a first mode and a main antenna of a second mode, an auxiliary antenna comprising an auxiliary antenna of the first mode and an auxiliary antenna of the second mode, and an antenna bracket. The main and auxiliary antennas are fixed on a same antenna bracket, each of which is configured with a spring lea. When the antenna bracket is clasped on a main board, four spring leaves of the main and auxiliary antennas contact with four antenna feeding points on the main board respectively, An LC resonant circuit is disposed ahead of each antenna feeding point, and four LC resonant circuits resonate at a working frequency band of the antenna corresponding to the antenna feeding point with which each said LC resonant circuits connects, respectively.

Abstract: A system on a chip (SoC) includes a transceiver comprising a transmitter and a receiver, wherein at least one of the transmitter and receiver has a configurable portion that can be configured to operate in a single ended mode and in a differential mode. Two interface pins are provided for coupling the transceiver to an antenna via a matching network, wherein the two interface pins are shareably coupled to the transmitter and to the receiver. A tunable capacitor is coupled to differential signal lines of the configurable portion, wherein the tunable capacitor is configured to be tuned to optimize impedance matching of the configurable portion for each mode of operation.

Abstract: A system on a chip (SoC) includes a transceiver comprising a transmitter and a receiver, wherein at least one of the transmitter and receiver has a configurable portion that can be configured to operate in a single ended mode and in a differential mode. Two interface pins are provided for coupling the transceiver to an antenna via a matching network, wherein the two interface pins are shareably coupled to the transmitter and to the receiver. A tunable capacitor is coupled to differential signal lines of the configurable portion, wherein the tunable capacitor is configured to be tuned to optimize impedance matching of the configurable portion for each mode of operation.

Abstract: A multi-band antenna system for MIMO applications is adapted to provide high isolation between antennas across a wide range of frequencies. Multiple Isolated Magnetic Dipole (IMD) antennas are co-located and connected with a feed network that can include switches that adjust phase length for transmission lines connecting the antennas. Filtering is integrated into the feed network to improve rejection of unwanted frequencies. Filtering can also be implemented on the antenna structure. Either one or multi-port antennas can be used.

Abstract: An active antenna system with multiple feed ports and a control method of the active antenna system are provided. The active antenna system includes an antenna radiation element, a first feed port and a second feed port. If the first control circuit is in a close state, the first feed port and a first physical position of the antenna radiation element are connected with each other, so that a signal is fed to the antenna radiation element through the first feed port and the first physical position. If the second control circuit is in the close state, the second feed port and a second physical position of the antenna radiation element are connected with each other, so that the signal is fed to the antenna radiation element through the second feed port and the second physical position.

Abstract: A communication device is provided with a band elimination filter that has one end connected to an antenna terminal, and a first multiplexer that is connected to the other end of the band elimination filter. The band elimination filter is configured to eliminate signals of a frequency band that is different from the frequencies of signals transmitted and received in the first multiplexer, and is configured from a filter circuit that includes a bulk wave element.

Abstract: Tunable duplexers and related methods are disclosed for use in communications networks. A tunable radiating duplexer can include a first antenna comprising a first variable capacitor and a second antenna comprising a second variable capacitor.

Abstract: A multi band antenna device which can simultaneously design a first frequency band antenna and a second frequency band antenna within one wireless communication device is provided. The multi band antenna device includes a first band antenna unit that communicates a first frequency band signal, a first band driving circuit unit that is connected to the first band antenna unit and that is configured to perform signal processing of a corresponding first frequency band signal communicated in the first band antenna unit, a second band driving circuit unit that is connected to the first band antenna unit, and that is configured to perform signal processing of a second frequency band signal which has a frequency that is lower than a frequency of the first frequency band signal, and a first inductor unit that is connected between one end of the first band antenna unit and the second band driving circuit unit, and that is configured to serve as an inductor.

Abstract: A modular feed network is provided with a segment base provided with a feed aperture, a corner cavity at each corner and a tap cavity at a mid-section of each of two opposite sides. A segment top is provided with a plurality of output ports. The segment top is dimensioned to seat upon the segment base to form a segment pair. the segment base provided with a plurality of waveguides between cavities of the segment base. The modular feed network is configurable via a range of feed, bypass and/or power divider taps seated in the apertures and/or cavities to form a waveguide network of varied numbers of output ports by routing across one or more of the segment tops. For example, the modular feed network may comprise 1, 4 or 16 of the segment bases retained side to side.

Abstract: Methods for antenna switch modules are disclosed. In certain implementations, a method of making an antenna switch module is provided. The method includes providing a package substrate implemented to receive one or more electrical components, attaching a silicon on insulator (SOI) die to the package substrate, and providing an integrated filter. The SOI die includes a capacitor and a switch coupled to a plurality of radio frequency (RF) signal paths. The integrated filter filters an RF signal received on a first RF signal path of the plurality of RF signal paths, and includes the capacitor of the SOI die and an inductor.

Abstract: The present invention is an integrated antenna assembly which allows for integration of a first radio system and a second radio system with the integrated antenna assembly. The integrated antenna assembly may include a coupler for providing sufficient isolation between the first radio system (ex.—a vertical polarization system) and the second radio system (ex.—a horizontal polarization system). The integrated antenna assembly may further include a common mode choke connected between a first antenna element and a second antenna element of the integrated antenna assembly. The coupler may produce a common mode based on signals received from the vertical polarization system and may also produce a differential mode based on signals received from the horizontal polarization system. The common mode choke may be configured for: preventing transmission of common mode currents from the first antenna element to the second antenna element; and being transparent to differential mode current flow.

Abstract: A module includes: a duplexer including an antenna terminal; a first wiring connecting the antenna terminal to an antenna; a second wiring coupled to the antenna terminal without the first wiring; and an inductor coupled to the second wiring.

Abstract: A circuit for a wideband electrical balance duplexer (EBD) may include a first impedance element and a second impedance coupled between a first and a second node and a second and a third node of the bridge circuit, respectively. An antenna may be coupled between the first and a fourth node of the bridge circuit to receive and transmit RF signals. A balancing network may provide an impedance substantially matching an impedance of the antenna. The balancing network may be coupled between the third and the fourth node of the bridge circuit. The first or the second impedance elements may facilitate balancing the bridge circuit. One or more output nodes of a transmit path may be coupled to an input node of the bridge circuit. One or more input nodes of a receive path may be coupled between the second and the fourth node of the bridge circuit.

Abstract: A high-frequency module includes a semiconductor chip device that is mounted on an external circuit substrate by wire bonding. A switch forming section, a power amplifier forming section and a low noise amplifier forming section, realized by a group of FETs, which are active elements, are formed in the semiconductor chip device. Flat plate electrodes, which form capacitors are formed in the semiconductor chip device. Conductor wires that connect the external circuit substrate and the semiconductor chip device function as inductors. A group of passive elements that includes inductors and capacitors is formed. As a result, a high-frequency module that can be reduced in size while still obtaining the required transmission characteristic is realized.

Abstract: An integrated circuit includes a plurality of circuits including a plurality of millimeter wave interfaces for communicating data between the plurality of circuits via millimeter wave RF signaling. A power supply line supplies at least one power supply signal to the plurality of circuits. The power supply line includes a plurality of antenna elements to facilitate the communicating of first data between the plurality of circuits via the millimeter wave RF signaling.

Abstract: A compact antenna element and assembly using a directly fed and electromagnetically coupled step probe element for ultra wideband application. It achieves very good impedance match, isolation and pattern stability across a wide frequency band. The compact ultra wideband radiating element covers all known radio frequency bands in the mobile base station industry to date.

Abstract: A high-frequency module includes a switch IC and a matching circuit. The high-frequency module includes a multilayer body. The switch IC and an inductor of the matching circuit are mounted on a top surface of the multilayer body. A top-surface land electrode on which a common terminal of the switch IC is mounted is connected to one end of a wiring conductor through a via-conductor. The other end of the wiring conductor is connected to a top-surface land electrode on which a terminal electrode at one end of the inductor is mounted, through a via-conductor. An end portion of the inductor on the side connected to the common terminal of the switch IC is disposed near the common terminal. Thus, the length of the wiring conductor is shortened and a parasitic capacitance is decreased.

Abstract: Systems and methods are disclosed for shared AM/FM air loop antennas that may be advantageously implemented to provide a AM/FM receiver system with a single common air loop antenna for receiving both AM and FM channels, thus eliminating the need for additional materials and electronics associated with provision of a separate FM pigtail antenna and FM antenna jack for connection of same. The shared AM/FM air loop antennas may be connected to a radio device having antenna connections.

Abstract: A multi-band antenna system for MIMO applications is adapted to provide high isolation between antennas across a wide range of frequencies. Multiple Isolated Magnetic Dipole (IMD) antennas are co-located and connected with a feed network that can include switches that adjust phase length for transmission lines connecting the antennas. Filtering is integrated into the feed network to improve rejection of unwanted frequencies. Filtering can also be implemented on the antenna structure. Either one or multi-port antennas can be used.

Abstract: A communications apparatus. The apparatus comprises a transmitting antenna, a receiving antenna, a first serial configuration of a first power amplifier and a first matching network for producing a first signal, the first power amplifier operating in a first frequency band, a second serial configuration of a second power amplifier and a second matching network for producing a second signal, the second power amplifier operating in a second frequency band, a first switching element for switchably supplying the first signal or the second signal to the transmitting antenna, a first and a second receiver; and a second switching element for switchably directing a signal received at the receiving antenna to the first receiver or the second receiver.

Abstract: An integrated antenna system is disclosed which may include a first antenna sub-system. The integrated antenna system may further include a second antenna sub-system. The first antenna sub-system may be a Ku-band antenna sub-system. The second antenna sub-system may be one of: an L-band antenna sub-system or a C-band antenna sub-system. The second antenna sub-system may be tightly/seamlessly integrated with the first antenna sub-system, thereby providing a system with integrated antenna bands which provides omni-directional coverage.

Abstract: A high-frequency module includes first and second demultiplexers and a band elimination filter. The first and second demultiplexers include common terminals, transmission filters, and reception filters, respectively. In the band elimination filter, a demultiplexer-side terminal is connected to the common terminal of the first demultiplexer. The band elimination filter includes a first pass band, and a second pass band and a stop band that are located adjacent to each other within the first pass band. The band elimination filter is configured so that the second pass band includes the pass band of each of the transmission filter and the reception filter in the first demultiplexer and the stop band includes the pass band of the transmission filter in the second demultiplexer.

Abstract: Multi-use antenna techniques are described. In one or more implementations, a device includes a single fixed radiating structure, a first branch coupled to the single fixed radiating structure to tune to a first frequency range to support a first wireless signal technique, and a second branch coupled to the single fixed radiating structure to tune to a second frequency range to support a second wireless signal technique, the second frequency range being different than the first frequency range.

Abstract: An antenna system comprises a plurality of conductors, a combiner, and a plurality of loads. The combiner has an output port. The plurality of loads connects the plurality of conductors to each other in line. The plurality of loads has an impedance equal to a desired impedance for the output port. The combiner combines power received by the plurality of loads at the output port of the combiner.

Abstract: Distributed band reject filters are disclosed. A band reject filter includes a first acoustic resonator and a second acoustic resonator, each of which has either shunt resonators adapted to resonate substantially at respective resonance frequencies defining a rejection frequency band or series resonators adapted to anti-resonate substantially at respective anti-resonance frequencies defining the rejection frequency band. These resonators are connected through a phase shifter which imparts an impedance phase shift of approximately 45° to 135°. Exemplary applications of the band reject filters disclosed herein include implementation as an inter-stage band reject filter for a base station power amplifier for a wireless communication system, as a radio frequency band reject filter in a duplexer for a wireless communication terminal, and in a low noise amplifier input stage.

Abstract: An antenna includes a waveguide having an aperture at a first end and a conducting component at a second end, the conducting component shorting the waveguide and a first set of two orthogonal dipoles, fed in quadrature, the orthogonal dipoles located near the aperture of the waveguide operating close to its dominant mode cut off frequency.

Abstract: A communication system includes the following elements: a transmitter including a transmission circuit unit configured to generate an RF signal for transmitting data and an electric-field-coupling antenna configured to transmit the RF signal as an electrostatic field; a receiver including an electric-field-coupling antenna and a reception circuit unit configured to receive and process the RF signal received by the electric-field-coupling antenna; and a surface-wave propagation medium configured to provide a surface-wave transmission line to transmit a surface wave emanating from the electric-field-coupling antenna of the transmitter with low propagation loss.

Abstract: The invention refer to a wireless handheld or portable device including an antenna system (250) capable of operation in a first frequency region and in a second frequency region, wherein the highest frequency of the second frequency region is lower than the lowest frequency of the first frequency region, the antenna system (250) comprising an antenna structure (260) including: an antenna element (251) having a first connection point (253a) and a second connection point (253b); a ground plane layer (202) having at least one connection point (204); a first internal port (261), said first port being defined between the first connection point (253a) of the antenna element (251) and one of the at least one connection point (204) of the ground plane layer (202); and a second internal port (262), said second port (262) being defined between the second connection point (253b) of the antenna element (251) and one of the at least one connection point (204) of the ground plane layer (202); the antenna system further com

Abstract: An antenna module is provided and includes two feeding parts and having different frequencies of feeding on a circuit board. A first feeding radiation electrode is connected to the feeding part on a lower frequency side and performs an antenna operation. A second feeding radiation electrode is connected to the feeding part on a higher frequency side and performs an antenna operation. The first and second feeding radiation electrodes electrically connected, and the second feeding radiation electrode is smaller than and on the first feeding radiation electrode with an insulating part therebetween. The first feeding radiation electrode is configured to serve as an electrode that also performs an antenna operation of the second feeding radiation electrode, in such a manner that the second feeding radiation electrode performs an antenna operation in which the second feeding radiation electrode and the first feeding radiation electrode are electrically coupled to each other.

Abstract: A communication system transmits signals having frequencies that lie within a transmission band and receives signals having frequencies that lie within a reception band. The system includes a duplexer and an antenna. The duplexer includes a transmission branch and a reception branch. The transmission branch includes a transmission filter, a transmission phase shifting network and a transmission matching network. The reception branch includes a reception filter, a reception phase shifting network and a reception matching network. The transmission matching network and the reception matching network have predominately constant phase shifts over frequencies within the reception band and within the transmission band, respectively. The antenna is coupled to the transmission matching network and to the reception matching network, and shows a predominantly reactance-only impedance variation over frequencies in the transmission band and over frequencies in the reception band.

Abstract: An antenna element has first and second feed ports, and is simultaneously excited through the feed ports so as to simultaneously operate as first and second antenna portions respectively, associated with the feed ports. The antenna element is excited at one of a first frequency and a second frequency higher than the first frequency. An antenna apparatus is provided with: a slit that provides isolation between the feed ports; a trap circuit that allows the slit to provide isolation at the first or second frequency when the antenna element is excited at the first or second frequency; and a reactance element that shifts a frequency at which the slit provides isolation between the feed ports, to the first frequency, when the antenna element is excited at the first frequency.

Abstract: A communication system includes the following elements: a transmitter including a transmission circuit unit configured to generate an RF signal for transmitting data and an EFC antenna configured to transmit the RF signal as an electrostatic field or an induced electric field; a receiver including an EFC antenna and a reception circuit unit configured to receive and process the RF signal received by the EFC antenna; and an impedance snatching unit configured to make an impedance of the EFC antenna of the transmitter equal to an impedance of the EFC antenna of the receiver. The RF signal is transmitted by electric-field coupling between the EFC antennas, facing each other, of the transmitter and the receiver.

Abstract: A transmitter unit which is disposed between the first base station and the antenna arrangement contains a device for aggregate signal forming, a D/A converter and a transmission power amplifier. The first base station is connected on the output side to the device for aggregate signal forming such that a digital output signal of the first base station reaches the device for aggregate signal forming as the first input signal. The device for aggregate signal forming is connected on the output side to the antenna arrangement via the D/A converter and the transmission power amplifier such that an aggregate signal formed by the device for sum forming reaches the antenna arrangement, the aggregate signal being formed from the first digital input signal and a second digital input signal connected to the device for aggregate signal forming.

Abstract: An antenna duplexer includes a transmission filter and a reception filter both coupled with an antenna terminal. A pass band of the transmission filter is lower than a pass band of the reception filter. The transmission filter includes a first series resonator coupled with a first terminal, a second series resonator connected to the first series resonator at a first node, a first parallel resonator connected to a first port of the first series resonator, a second parallel resonator connected to a first node and the first parallel resonator at a second node, a third parallel resonator connected to the first node, a fourth parallel resonator connected to the third parallel resonator at a third node, a first inductance element coupled with the second node and a ground, and a second inductance element coupled with the third node and the ground. The first and second parallel resonators and the first inductance element produce an attenuation pole at a frequency lower than a pass band of the transmission filter.

Abstract: A communication system includes the following elements: a transmitter including a transmission circuit unit configured to generate an RF signal for transmitting data and an electric-field-coupling antenna configured to transmit the RF signal as an electrostatic field; a receiver including an electric-field-coupling antenna and a reception circuit unit configured to receive and process the RF signal received by the electric-field-coupling antenna; and a surface-wave propagation medium configured to provide a surface-wave transmission line to transmit a surface wave emanating from the electric-field-coupling antenna of the transmitter with low propagation loss.