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EP-4254649-B1 - DIGITAL PHASE SHIFTER

EP4254649B1EP 4254649 B1EP4254649 B1EP 4254649B1EP-4254649-B1

Inventors

  • UEMICHI YUSUKE
  • YAMAGUCHI YO

Dates

Publication Date
20260506
Application Date
20220808

Claims (10)

  1. A digital phase shifter (100) comprising: a plurality of digital phase shift circuits (10) connected in cascade; and one or more bend-type connection units (20) each configured to make a connection between two digital phase shift circuits (10) of the plurality of digital phase shift circuits (10), wherein each of the digital phase shift circuits (10) includes at least a signal line (1), a pair of inner lines (2) provided at both sides of the signal line (1), a pair of outer lines (3) provided outside of the inner lines (2), a first ground conductor (4, 4a) connected to one ends of the inner lines (2) and the outer lines (3), a second ground conductor (4, 4b) connected to the other ends of the outer lines (3), and a pair of electronic switches (7, 7a, 7b) provided between the other ends of the inner lines (2) and the second ground conductor (4, 4b), wherein each of the digital phase shift circuits (10) is a circuit configured to be set in a low-delay mode in which a return current flows through the inner line (2) or a high-delay mode in which a return current flows through the outer line (3), and characterized in that the plurality of digital phase shift circuits (10) connected in cascade are arranged in a spiral shape via the connection units (20).
  2. The digital phase shifter (100) according to claim 1, further comprising a transmission line (31) connected to the signal line (1) of a terminal digital phase shift circuit that is the digital phase shift circuit (10) located at an innermost circumference among the plurality of digital phase shift circuits (10) arranged in the spiral shape and configured for transmission therethrough of a high-frequency signal flowing through the signal line (1), wherein the transmission line (31) is formed on a layer different from a layer where the signal line (1) is formed.
  3. The digital phase shifter (100) according to claim 1, further comprising a transmission line (31) connected to the signal line (1) of a terminal digital phase shift circuit that is the digital phase shift circuit (10) located at an innermost circumference among the plurality of digital phase shift circuits (10) arranged in the spiral shape and configured for transmission therethrough of a high-frequency signal flowing through the signal line (1), wherein the transmission line (31) is formed above or below the connection unit (20).
  4. The digital phase shifter (100) according to claim 2 or 3, further comprising a transmission-unit ground layer (33) arranged at least one of above and below the transmission line (31), wherein the transmission-unit ground layer (33) is connected to at least one of the inner line (2) and the outer line (3) via a transmission-unit via-hole (51, 52).
  5. The digital phase shifter (100) according to claim 4, comprising a ground line (32) connected to the inner line (2) of the terminal digital phase shift circuit and extending along the transmission line (31).
  6. The digital phase shifter (100) according to claim 5, wherein the transmission-unit ground layer (33) is connected to at least the ground line (32) via the transmission-unit via-hole (51, 52) or a via-hole different from the transmission-unit via-hole (51, 52).
  7. The digital phase shifter (100) according to any one of claims 1 to 6, wherein the connection unit (20) has a structure that is bent at 90 degrees.
  8. The digital phase shifter (100) according to any one of claims 1 to 7, wherein the connection unit (20) includes: a first connection line (21) configured to connect the signal line (1) of one digital phase shift circuit of the two digital phase shift circuits (10) and the signal line (1) of the other digital phase shift circuit of the two digital phase shift circuits (10); a second connection line (22) configured to connect the inner line (2) of the one digital phase shift circuit and the inner line (2) of the other digital phase shift circuit; and a connection-unit ground layer (24, 25) arranged at least one of above and below the first connection line (21).
  9. The digital phase shifter (100) according to claim 8, further comprising a third connection line (23) configured to connect the outer line (3) of the one digital phase shift circuit and the outer line (3) of the other digital phase shift circuit.
  10. The digital phase shifter (100) according to claim 8 or 9, wherein the second connection line (22) and the connection-unit ground layer (24, 25) are connected by a connection-unit via-hole (40, 42).

Description

[Technical Field] The present invention relates to a digital phase shifter. Priority is claimed on Japanese Patent Application No. 2022-022266, filed February 16, 2022. [Background Art] The document "A Ka-band Digitally-Controlled Phase Shifter with Sub-degree Phase Precision" (2016, IEEE, RFIC) describes a digitally controlled phase shift circuit for high-frequency signals such as microwaves, sub-millimeter waves, or millimeter waves (a digital phase shift circuit). A large number of digital phase shift circuits are mounted on a semiconductor substrate in a state in which the digital phase shift circuits are connected in cascade. That is, the digital phase shift circuit is a unitary unit in the configuration of an actual digital phase shifter and a desired function is exhibited by connecting several tens of digital phase shift circuits in cascade. The digital phase shift circuit includes at least a signal line, a pair of inner lines provided at both sides of the signal line, a pair of outer lines provided outside of the inner lines, a first ground conductor connected to one ends of the inner lines and the outer lines, a second ground conductor connected to the other ends of the outer lines, and a pair of electronic switches provided between the other ends of the inner lines and the second ground conductor. The digital phase shift circuit switches an operation mode to a low-delay mode or a high-delay mode by switching a return current flowing through a pair of inner lines or a pair of outer lines due to the transmission of a high-frequency signal in the signal line in accordance with an open or closed state of each of the pair of electronic switches. That is, in the digital phase shift circuit, the operation mode is the low-delay mode when a return current flows through the pair of inner lines and the operation mode is the high-delay mode when a return current flows through the pair of outer lines. The article SADHU BODHISATWA ET AL: "A 28-GHz-Element TRX Phased-Array IC With Concurrent Dual-Polarized Operation and Orthogonal Phase and Gain Control for 5G Communications", IEEE JOURNAL OF SOLID-STATE CIRCUITS, IEEE, USA, vol. 52, no. 12, H03K5/00, 1 December 2017 describes a 28-Ghz Phased-Array IC for 5G communications. US 10 291 282 B1 describes a radio-frequency transceiver front-end circuit. The article YISHAY ROEE BEN ET AL: "PVT Robust Passive Phase Shifter for 5G MIMO Applications", 2020 IEEE 20TH TOPICAL MEETING ON SILICON MONOLITHIC INTEGRATED CIRCUITS IN RF SYSTEMS (SIRF), IEEE, 26 January 2020 describes an integrated Ka-Band phase shifter with near-constant insertion-loss for 5G phased array applications. [Summary of Invention] [Technical Problem] When the configuration of the digital phase shifter is a configuration in which the above digital phase shift circuits are connected in a line, the length of the digital phase shifter increases. In order to shorten the length of the digital phase shifter, a configuration in which the configuration of the digital phase shifter is bent using a connection unit such as a bend-type line having a bent structure is conceivable. When the configuration of the digital phase shifter is bent, the number of portions where return currents flowing through outer lines of two digital phase shift circuits arranged to face each other are opposite each other may increase according to a bending method. In these portions, if a distance between the outer lines of the digital phase shift circuit arranged to face each other is excessively short, magnetic fields generated in the outer lines weaken each other. Thus, from the viewpoint of the phase shift operation of the digital phase shifter, it is desirable that the digital phase shifter have a bent configuration so that there are as few portions where magnetic fields generated in the outer lines weaken each other as possible. The present invention is made in view of such circumstances and an objective of the present invention is to provide a small-sized digital phase shifter capable of reducing the number of portions where magnetic fields generated in outer lines weaken each other. [Solution to Problem] According to an aspect of the present invention, there is provided a digital phase shifter including: a plurality of digital phase shift circuits connected in cascade; and one or more bend-type connection units each configured to make a connection between two digital phase shift circuits of the plurality of digital phase shift circuits, wherein each of the digital phase shift circuits includes at least a signal line, a pair of inner lines provided at both sides of the signal line, a pair of outer lines provided outside of the inner lines, a first ground conductor connected to one ends of the inner lines and the outer lines, a second ground conductor connected to the other ends of the outer lines, and a pair of electronic switches provided between the other ends of the inner lines and the second ground conductor, wherein each of th