CN101257286B - Antenna multiplexer with a pi-network circuit and use of a pi-network circuit - Google Patents

Abstract

An antenna multiplexer is described having a Π-type network circuit comprising a series-connected inductor and a parallel-connected capacitor on each of the two wiring sides of the inductor. The Π-type network circuit is used to realize the impedance mismatch of the signal path of the antenna multiplexer.

Description

Antenna multiplexer with ∏-type network circuit and application of ∏-type network circuit

technical field

The invention relates to an antenna multiplexer (multiplexer) with a Π-type network circuit and the application of the Π-type network circuit.

Background technique

In an antenna multiplexer with several signal paths, it is desirable that a signal passing through one of the signal paths interfere with the other paths and/or signals assigned to the other signal paths as little as possible.

Contents of the invention

According to an embodiment of the present invention, an antenna multiplexer having a Π-type network circuit is provided. A Π-type network circuit includes an inductance connected in series and a capacitance connected in parallel on each of the two wiring sides of the inductance.

According to another embodiment of the present invention, a Π-type network circuit is used to realize the impedance mismatch of the signal path of the antenna multiplexer, the Π-type network circuit comprises an inductor connected in series and each of the two connection sides of the inductor side, parallel connected capacitors.

Description of drawings

Embodiments of the invention are shown in a single drawing and are discussed in more detail below.

Fig. 1 shows a block diagram of an antenna multiplexer according to an embodiment of the present invention.

Detailed ways

The embodiments described below in connection with antenna multiplexers are similarly applicable to the application of Π-type network circuits, and vice versa.

An antenna multiplexer includes multiple signal paths. The antenna multiplexer is used to connect a transmitting or receiving unit or a combined transmitting/receiving unit to several antennas, or to connect an antenna to several transmitting and/or receiving units. The signals assigned to the different signal paths can be present in a time-shifted or synchronous manner, that is to say they can be received and/or transmitted in a time-shifted or synchronous manner. A multiplexer with two signal paths is also called a duplexer, and a multiplexer with three signal paths is also called a triplexer. For example, if an antenna multiplexer connects a transmit and receive unit to an antenna, this is also called a transmit/receive antenna duplexer.

Antenna multiplexers in mobile radiotelephones of CDMA and WCDMA systems (such as UMTS or PCS) for example have the function of filtering the incoming (from the antenna) signal and the signal to be transmitted (from the power amplifier), and thus, the An antenna multiplexer is a transmit/receive duplexer. In this duplex operation, the input signal and the output signal pass through the duplexer simultaneously. In contrast to TDMA systems (eg, GSM), in which signals are received and transmitted in a time-shifted manner, CDMA and/or WCDMA systems do not use switches to switch between signal paths. In synchronous duplex operation, high isolation and stop-band rejection present considerable challenges. The transmit signal path (Tx) may include a transmit signal filter (Tx filter), and the receive signal path (Rx) may include a receive signal filter (Rx filter). To isolate the two Tx and Rx filters from each other, phase shifters can be provided. The task of this phase shifter is to transform the low-impedance Rx input impedance in the Tx passband frequency range to a high-impedance Rx input impedance in order to ensure good isolation. At the same time, it is preferable to avoid degrading the input impedance of the Rx filter in the Rx reception frequency range.

According to an embodiment of the invention, a Π-type network is used as a phase shifter, the Π-type network circuit comprising a series connected inductor and a parallel connected capacitor on each of the two wiring sides of the inductor. Such a device layout is called a Π-network circuit, Π-network or Π-filter because the usual graphical representation of such a device layout in a circuit diagram resembles the Greek letter "Π". The Π-type network circuit used as a phase shifter can convert the low-impedance Rx input impedance to a high-impedance input impedance in the Tx passband frequency range, and in addition can well match the input impedance of the Rx filter in the Rx passband frequency range . The arrangement for the Π-type network circuit can be realized in compact form as distributed structural components on a laminated board serving as a carrier substrate. A phase shifter implemented as a Π-network circuit may be implemented on a thin carrier substrate, such as a four-layer laminate with metallized planes spaced in the range from 70 microns to 60 microns or less.

According to an embodiment of the present invention, an antenna multiplexer includes an antenna wire and a plurality of signal wires, wherein a Π-type network circuit is arranged in a signal path between the antenna wire and one of the signal wires.

According to an embodiment of the present invention, the Π-type network circuit is configured to achieve an impedance mismatch of the signal path for signals present on the wiring side of the antenna.

According to an embodiment of the present invention, the Π-type network circuit is configured to transform the low-impedance input impedance of the signal path to a high-impedance input impedance with a phase shift of 180 degrees.

According to various embodiments of the invention, the signal path is a receive signal path.

According to various embodiments of the present invention, the signal path is a receive signal path, and the antenna multiplexer further includes a transmit signal path, wherein the Π-type network circuit is configured to convert the low impedance input impedance of the receive signal path to that of the transmit signal path High impedance input impedance over the transmit frequency range.

According to various embodiments of the invention, the signal path is a transmit signal path.

According to various embodiments of the present invention, the signal path is a first transmit signal path, and the antenna multiplexer further includes a second transmit signal path, wherein the Π-type network circuit is configured to convert the second transmit signal path within the transmit frequency range The low-impedance input impedance of the first transmit signal path is converted to a high-impedance input impedance.

According to an embodiment of the invention, the antenna multiplexer is a mobile radiotelephone antenna multiplexer.

According to various embodiments of the present invention, the mobile radiotelephone antenna multiplexer is a CDMA or WCDMA mobile radiotelephone antenna multiplexer.

According to various embodiments of the invention, the inductance of the Π-type network circuit is configured as a high-impedance microstrip of a multilayer laminate.

According to various embodiments of the present invention, the inductance of the Π-type network circuit is configured as an SMD device (Surface Mounted Device).

According to various embodiments of the invention, at least one capacitance of the Π-type network circuit is configured as a parallel-plate capacitor whose plates are arranged in two adjacent metallization planes of the multilayer laminate.

According to various embodiments of the invention, the inductance of the Π-type network circuit has a value between 0.2nH and 100nH. A Π-type network circuit with this value can be used in an antenna multiplexer for a mobile radiotelephone.

According to various embodiments of the invention, the inductance of the Π-type network circuit has a value between 1 nH and 20 nH. A Π-type network circuit with this value is particularly suitable for isolating the receive signal path from the transmit signal path.

According to various embodiments of the invention, the two capacitances of the Π-type network circuit each have a value between 0.05 pF and 30 pF. A Π-type network circuit with these values can be used in an antenna multiplexer for a mobile radiotelephone.

According to various embodiments of the invention, the two capacitances of the Π-type network circuit each have a value between 0.3 pF and 6 pF. Π-type network circuits with these values are particularly suitable for isolating the receive signal path from the transmit signal path.

According to an embodiment of the present invention, the Π-type network circuit is used to realize the impedance mismatch of the signal path of the antenna multiplexer, which signal path has a low-impedance input impedance at the antenna connection side, and the Π-type network circuit connects the low-impedance input impedance Converts to high impedance input impedance.

According to an embodiment of the present invention, the antenna multiplexer further includes a transmit signal path, and the Π-type network circuit acts as a phase shifter in the transmit frequency range of the transmit signal path, which separates the signal path from the transmit signal path isolation.

Referring to FIG. 1, a block diagram of an antenna multiplexer according to an embodiment of the present invention will be described in more detail below.

The block diagram shows a transmit/receive antenna duplexer, as is required, for example, in mobile radiotelephones of the PCS mobile radio system. The duplexer 100 has a transmit signal path 101 with a transmit signal input 102 and a transmit signal filter 103 . The duplexer furthermore has a receive signal path 104 with a receive signal output 105 and a receive signal filter 106 . Both the transmit signal path 101 and the receive signal path 104 are connected to a common antenna connection 107 .

The receive signal path 104 further includes a phase shifter 108 . The phase shifter is implemented as a Π-type network circuit. Within the circuit block called phase shifter 108, a circuit diagram of the Π-type network circuit is schematically represented. An inductor 109 is shown connected in series to the receive signal path 104 .

Furthermore, capacitors 110 and 111 connected in parallel to the receive signal path are located on each of the two wiring sides of the inductance. To illustrate this parallel connection, two ground connections 112 and 113 are drawn, which are connected to the side of the connections of capacitors 110 and 111 remote from the receive signal path.

The low-impedance input impedance of the receive signal filter 106 is transformed into a high-impedance input impedance in the transmit frequency range, ie into the passband of the transmit signal filter 103, by means of the phase shifter 108, which is implemented as a Π-type network circuit High-Z input impedance in the range. This serves to isolate the receive signal filter 106 and the transmit signal filter 103 from each other, that is, the receive signal path 104 and the transmit signal path 101 from each other. Furthermore, the Π-type network circuit is dimensioned such that in the receive frequency range the receive signal filter 106 is impedance-adapted sufficiently well to the antenna impedance.

The arrangement of the Π-type network circuit is realized in a very compact manner as a distributed structural component on a four-layer laminate as carrier substrate. The inductor 109 is a coil realized by a high-impedance microstrip line. In a four-layer laminate, the signal lines are in the first metallization plane and the ground is in the third metallization plane. The two capacitors 110 and 111 connected in parallel are accommodated in the third and fourth metallization planes in the form of parallel-plate capacitors.

The transmit signal filter 103 and the receive signal filter 106 are implemented as bulk acoustic wave filters (BAW). An advantageous emission characteristic of the antenna duplexer results when the inductance 109 has a value of 3.6 nH to 5.2 nH and the two capacitances 110 and 112 each have a value of 1 pF to 2 pF. A four-layer laminate was patterned with metallized planes spaced 70 microns, 60 microns, and 70 microns apart.

According to another embodiment of the present invention, an antenna multiplexer with a Π-type network circuit comprising a series connected inductor and a parallel connection on each of the two wiring sides of the inductor is provided. capacitance, and the antenna multiplexer has an antenna wire and a receive signal output coupled to the antenna wire, wherein the Π-type network circuit is arranged in a signal path between the antenna wire and the receive signal output.

According to this and other embodiments of the invention, the antenna multiplexer includes a receive signal filter arranged in the signal path between the Π-type network circuit and the receive signal output.

According to this and other embodiments of the invention, the antenna multiplexer includes a transmit signal input coupled to the antenna wire, wherein the signal path between the transmit signal input and the antenna wire is on the side of the antenna wire up to the branch and the antenna wire shared with the signal path between the received signal output end, and wherein the Π-shaped network circuit is arranged in the signal path between the branch and the received signal output end.

According to this and other embodiments of the invention, the antenna multiplexer includes a transmit signal filter arranged in the signal path between the transmit signal input and the branch.

Claims (17)

1. Antenna multiplexer, including: a П-type network circuit comprising an inductance connected in series and a capacitance coupled in parallel on each of the two wiring sides of the inductance; An antenna wire and a plurality of signal wires coupled simultaneously to the antenna wire without a switch in between, wherein a П-type network circuit is arranged between the antenna wire and only one signal wire of said plurality of signal wires in the signal path; wherein the П-type network circuit is configured to achieve an impedance mismatch of the signal path for signals present at the wiring side of the antenna; and Wherein the П-type network circuit is configured to transform the low-impedance input impedance of the signal path into a high-impedance input impedance through a phase shift of 180 degrees. 2. The antenna multiplexer according to claim 1, wherein the signal path is a receive signal path. 3. The antenna multiplexer of claim 1, wherein the signal path is a first transmit signal path. 4. The antenna multiplexer of claim 1, wherein the antenna multiplexer is a mobile radiotelephone antenna multiplexer. 5. The antenna multiplexer of claim 4, wherein the mobile radiotelephone antenna multiplexer is a CDMA or WCDMA mobile radiotelephone antenna multiplexer. 6. The antenna multiplexer according to claim 1, wherein the inductance of the Ο-type network circuit is configured as a high-impedance microstrip line of a multilayer laminate. 7. The antenna multiplexer according to claim 1, wherein the inductance of the P-type network circuit is configured as an SMD device. 8. The antenna multiplexer according to claim 1, wherein at least one capacitor of the П-type network circuit is configured as a parallel-plate capacitor, the plates of which are arranged on two adjacent metallized plane. 9. The antenna multiplexer according to claim 1, wherein the inductance of the Ο-type network circuit has a value between 0.2nH and 100nH. 10. The antenna multiplexer according to claim 9, wherein the inductance of the P-type network circuit has a value between 1 nH and 20 nH. 11. The antenna multiplexer according to claim 1, wherein the two capacitances of the Ο-type network circuit each have a value between 0.05 pF and 30 pF. 12. The antenna multiplexer according to claim 11, wherein the two capacitances of the Ο-type network circuit each have a value between 0.3pF and 6pF. 13. Antenna multiplexer, including: a П-type network circuit comprising an inductance connected in series and a capacitance coupled in parallel on each of the two wiring sides of the inductance; An antenna wire and a plurality of signal wires coupled simultaneously to the antenna wire without a switch in between, wherein a П-type network circuit is arranged between the antenna wire and only one signal wire of said plurality of signal wires in the signal path of the A transmit signal path, wherein the P-type network circuit is configured to convert a low impedance input impedance of the receive signal path to a high impedance input impedance in the transmit frequency range of the transmit signal path. 14. Antenna multiplexer, including: a П-type network circuit comprising an inductance connected in series and a capacitance coupled in parallel on each of the two wiring sides of the inductance; An antenna wire and a plurality of signal wires coupled simultaneously to the antenna wire without a switch in between, wherein a П-type network circuit is arranged between the antenna wire and only one signal wire of said plurality of signal wires in the signal path of the A second transmit signal path, wherein the P-type network circuit is configured to convert the low impedance input impedance of the first transmit signal path to a high impedance input impedance in the transmit frequency range of the second transmit signal path. 15. Method of using a П-type network circuit in a signal path between an antenna wire and only one of a plurality of signal wires to achieve an impedance mismatch of a signal path of an antenna multiplexer, wherein the plurality of signal wires Simultaneously coupled to the antenna wires without a switch in between, the P-type network circuit includes an inductor connected in series and a capacitor coupled in parallel on each of the two wire sides of the inductor, wherein the signal path is at The antenna wiring side has a low-impedance input impedance, and the П-type network circuit converts the low-impedance input impedance to a high-impedance input impedance. 16. The method of using a П-type network circuit according to claim 15, wherein the antenna multiplexer further comprises a transmit signal path, and the П-type network circuit acts as a phase shifter in the transmit frequency range of the transmit signal path , the phase shifter isolates the signal path from the transmit signal path. 17. The method of using a П-type network circuit according to claim 15, wherein the antenna multiplexer is a mobile radiotelephone antenna multiplexer.

Images