Phase Shift Circuit Signal Line Segmentation for Frequency-Independent Tilt Control
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Solution Overview
Problem
Conventional phase shift circuits in antenna devices exhibit a frequency-dependent change in tilt angle due to the movement of dielectric members, which affects the consistency of radio wave emission patterns.
Innovation Solution
The phase shift circuit design incorporates a signal line with distinct regions of different dielectric member placements and characteristic impedances, where the first and third regions have smaller widths and thicknesses than the second region, allowing for controlled area ratios and reduced frequency dependence of tilt angle changes through movable dielectric members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional phase shift circuit with a single dielectric plate is used, then the tilt angle can be adjusted by varying the overlapped area, but the amount of tilt angle change becomes dependent on the input signal frequency
Solution Approach 1:
The signal line is divided into multiple regions (first region with higher characteristic impedance, second region with lower characteristic impedance, and third region with higher characteristic impedance) along the propagation direction. Multiple dielectric members are disposed in different regions, allowing independent control of phase shift in each region. This segmentation enables the circuit to compensate for frequency-dependent effects by balancing phase shifts across different impedance regions.
Solution Approach 2:
Different regions of the signal line are assigned different characteristic impedances by varying the width or thickness of the signal line in each region. The first and third regions have smaller widths/thicknesses (higher impedance) while the second region has larger width/thickness (lower impedance). This local variation in impedance creates different phase shift characteristics in each region that can be combined to achieve frequency-independent overall phase shift.
2Manufacturing precision
If the signal line width is reduced in regions with dielectric members, then the characteristic impedance increases for better phase control, but the signal line becomes more sensitive to manufacturing variations
Solution Approach 1:
The signal line is segmented into regions with different widths/thicknesses. By dividing the signal line into multiple sections with different characteristic impedances, the patent achieves better phase shift control in each region while distributing the manufacturing tolerance requirements across multiple regions rather than requiring high precision across the entire signal line.
Solution Approach 2:
The characteristic impedance of different regions is controlled by changing geometric parameters (width or thickness) of the signal line in each region. The first and third regions have smaller dimensions (higher impedance) while the second region has larger dimensions (lower impedance). This parameter variation allows optimization of phase shift characteristics while managing manufacturing tolerances.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design maintains a consistent tilt angle change relative to dielectric member movement, independent of input signal frequency, enhancing the stability and efficiency of radio wave emission in antenna devices.
Implementation Method 1
a first dielectric member and a second dielectric member which are disposed on a signal line along a propagation direction of a signal
Data Source
AI summary
An antenna device includes a plurality of phase shift circuits to which distributed signals are respectively input and a plurality of antenna elements to which signals output from the respective phase shift circuits are input. At least one of the plurality of phase shift circuits has a signal line in which a first region in which paired dielectric members are disposed, a second region in which no paired dielectric members is disposed and a third region in which paired dielectric members are disposed are provided in this order along a propagation direction of a signal. Moreover, a characteristic impedance of the first region in a state where the paired dielectric members are not disposed and a characteristic impedance of the third region in a state where the paired dielectric members are not disposed are higher than a characteristic impedance of the second region.