Disc Microstrip Antenna With Orthogonal Slots for Polarization Control
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Solution Overview
Problem
Existing microstrip antennas face challenges in achieving adjustable double linear polarization and frequency filtering without increasing footprint or causing interference, particularly when used in arrays with non-square or non-rectangular lattices.
Innovation Solution
A microstrip antenna design with disc-shaped transverse footprint and orthogonal slots, coupled with conductive lines and stubs, allows adjustable polarization and effective frequency filtering, compatible with various array formats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional square or rectangular microstrip antennas are used in square lattice arrays, then double linear polarization (h and v) can be achieved, but it is impossible to obtain +45° and −45° polarizations with the same pitch without antenna overlap
Solution Approach 1:
The patent transitions from conventional square/rectangular antenna elements to circularly symmetric disc-shaped radiating elements. This asymmetric change in geometry (from rectangular to circular) enables the antenna to achieve multiple polarization modes (+45°, -45°, h, v) without requiring different array configurations, as the circular symmetry allows equal coupling to all polarization directions.
Solution Approach 2:
The disc-shaped radiating element with orthogonal slots serves multiple functions: it can radiate in multiple polarization directions (h, v, +45°, -45°) using the same physical structure and array pitch. The single antenna design universally supports all linear polarizations by appropriate excitation of the orthogonal slots, eliminating the need for different antenna geometries for different polarization requirements.
2Duration of action of moving object
If the bandwidth of a microstrip antenna is decreased, then the antenna becomes resonant at harmonic frequencies (2nd harmonic, 3rd harmonic), but this generates parasitic radiation that must be filtered out
Solution Approach 1:
The patent converts the harmful parasitic radiation at harmonic frequencies into a beneficial frequency-selective filtering function. By intentionally designing the antenna to resonate at harmonic frequencies and then using orthogonal slots to selectively excite or suppress these modes, the antenna transforms unwanted harmonic radiation into a useful frequency discrimination capability, allowing the same structure to both widen bandwidth and reject out-of-band signals.
Solution Approach 2:
The orthogonal slots serve as intermediaries between the feeding network and the disc-shaped radiating element. These slots act as frequency-selective couplers that can selectively excite fundamental mode or harmonic modes depending on their dimensions and positioning, thereby mediating the energy transfer to achieve both wide bandwidth operation and harmonic rejection without requiring separate filtering components.
3Ease of manufacture
If slot-based electromagnetic coupling is used to excite the radiating element, then a wide frequency band can be generated and manufacturing is simplified, but the antenna footprint must be optimized to avoid overlap in non-square lattice arrays
Solution Approach 1:
The patent replaces conventional flat rectangular or square radiating elements with a disc-shaped (circular) radiating element. This curved geometry provides a more compact isotropic footprint that fits efficiently in triangular and hexagonal lattice arrangements, reducing the area required per element while maintaining omnidirectional radiation characteristics and simplifying the coupling to orthogonal slots for wideband operation.
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
Enables adjustable polarization and efficient frequency filtering, reducing interference and maintaining radiation efficiency, suitable for arrays with square, rectangular, or triangular lattices.
Implementation Method 1
Slot-based electromagnetic coupling allows a wide frequency band to be generated more easily. It also makes it possible to avoid any linking via between the radiating elements and the excitation
Implementation Method 2
a given elementary antenna will naturally become resonant at the frequencies at which its footprint is a multiple of a half-wavelength at the frequencies in question. The impedance of the elementary antenna is once again matched and it will be able to radiate anew
Data Source
AI summary
An elementary microstrip antenna includes a stack of layers, stacked in a direction z, the stack comprising: a first conductive radiating element of disc shape having a first centre, an axis in the direction z and passing through the first centre being called the central axis; a coupling assembly configured to couple an exciting device and the first radiating element, the coupling assembly comprising: a first slot comprising a centre called the slot centre located on the central axis; a second slot comprising a centre coincident with the slot centre, and substantially perpendicular to the first slot, the first and second slots each comprising circularly arcuate ends on the same circle centred on the slot centre; the slots and the stacked layers being configured so that a transverse footprint of the elementary antenna is disc-shaped.