Planar Antenna Isotropic Radiation via Channel Selection
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Solution Overview
Problem
Conventional planar antennas with isotropic radiation patterns face limitations in channel selection and radiation efficiency due to narrow microstrip lines, which restrict their application to specific frequency bands and increase energy loss.
Innovation Solution
A planar antenna design that includes a microstrip line set and a dipole antenna, with a channel selection element controlling the on/off states of channel units to generate high-frequency and low-frequency paths with different operating frequencies, allowing for selective switching between channels and improving radiation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If narrow microstrip lines are used to block high-frequency signals, then high-frequency blocking capability is improved, but energy loss increases and radiation efficiency deteriorates
Solution Approach 1:
The patent introduces a via hole as an intermediary element between the microstrip line and ground. This via hole provides an alternative path for high-frequency signal suppression without requiring the microstrip line to be extremely narrow. The via hole acts as a mediator that grounds high-frequency signals while allowing the microstrip line to maintain a reasonable width, thereby reducing energy loss and improving radiation efficiency.
2Device complexity
If fixed-position microstrip lines are used, then structural simplicity is improved, but channel selection capability deteriorates
Solution Approach 1:
The patent makes the microstrip line position dynamic by allowing it to be adjustable along the substrate. Instead of being fixed at a specific position, the microstrip line can be repositioned to select different communication channels. This dynamic positioning capability enables the antenna to adapt to various frequency bands and channels while maintaining a relatively simple overall structure.
3Loss of energy
If microstrip line width is increased to reduce energy loss, then radiation efficiency is improved, but high-frequency blocking capability deteriorates
Solution Approach 1:
The via hole serves as an intermediary that compensates for the reduced high-frequency blocking capability caused by wider microstrip lines. By providing an additional grounding path through the via hole, the system can use wider microstrip lines (reducing energy loss) while still maintaining effective high-frequency signal suppression.
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
The design enables the antenna to receive and transmit signals across multiple channels within various frequency bands with reduced energy loss and size constraints, enhancing communication performance and flexibility.
Implementation Method 1
Based on the Ampere's right-hand rule, the magnetic fields produced by the spiral radiating bodies 130 and 140 run through the first surface 111 (i.e., the magnetic field directions M12 and M13) with the current direction D11 and form a magnetic dipole.
Implementation Method 2
The impedance X of the microstrip line 132 satisfies X=ωL=(2πf)L, therefore the impedance X is in direct proportion to the frequency f and the inductance value L, which means the higher the frequency f or inductance L is, the greater the impedance X will be and accordingly the harder for high-frequency signals to pass through, wherein the length of the micro strip line 132 should be shorter than λg/4 wherein λg is a guided wavelength. In other words, the microstrip line 132 is like an inductive filter
Data Source
AI summary
A planar antenna with an isotropic radiation pattern is provided. The planar antenna includes a substrate, a dipole antenna, a microstrip line set, and a channel selection module. The dipole antenna is disposed on a first surface of the substrate, and the microstrip line set and the channel selection module are disposed on a second surface of the substrate. A first microstrip line and a second microstrip line of the microstrip line set are spirally extended along two opposite rotation trails on a vertical projection plane to form a high-frequency path with the dipole antenna. The planar antenna controls the on/off state of the channel selection module so that a low-frequency path is formed when the dipole antenna is connected to a first line and a second line. A plurality of channels having different operating frequencies is respectively generated within the high-frequency path and the low-frequency path.