Multilead Frame Coupler Antenna for Thin mm-Wave Atomic Clocks
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Solution Overview
Problem
The challenge in developing millimeter wave atomic clocks is to create a compact antenna structure that can efficiently operate at mm-wave frequencies while maintaining the necessary coupling reflector thickness of λ/4, which is typically achieved with thick antenna substrates, but package size constraints limit the overall dimensions, necessitating a thinner solution.
Innovation Solution
A multilayer lead frame with a conductive reflector wall and feed structure is used, where the reflector wall extends between the top and bottom ground planes, providing a lateral reflector and reducing the overall thickness of the coupler to less than λ/4, while maintaining efficient signal transfer and minimizing electromagnetic leakage and crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick antenna substrate is used to provide a coupling reflector at λ/4, then efficient signal coupling is achieved, but package size constraints are violated
Solution Approach 1:
The patent transitions from a conventional planar reflector configuration to a three-dimensional cavity-backed antenna structure. The reflector is positioned beneath the radiating element within a cavity formed by ground planes and side walls, creating a vertical dimension that provides the necessary λ/4 electrical length while maintaining a compact overall package footprint. This dimensional reconfiguration allows efficient coupling without requiring excessive substrate thickness.
Solution Approach 2:
The antenna structure is nested within a cavity formed by top and bottom ground planes connected by side walls. The radiating element is positioned within this cavity, and the reflector is nested beneath it, creating a compact nested configuration. This nesting approach consolidates multiple functional elements (radiating element, reflector, ground planes) into a single integrated structure that achieves the required electrical performance in a reduced thickness.
2Volume of stationary object
If package size is reduced to meet constraints, then compactness is achieved, but coupling reflector performance deteriorates
Solution Approach 1:
The patent applies different structural characteristics to different regions of the antenna assembly. The cavity walls and ground planes are configured with specific dimensions and conductive properties optimized for reflector performance, while the overall package envelope is minimized. The radiating element and reflector are positioned at specific locations within the cavity to maximize coupling efficiency. This localized optimization of critical regions maintains reflector performance while reducing overall package volume.
Solution Approach 2:
The patent optimizes key parameters including cavity dimensions, ground plane sizes, side wall heights, and the spacing between the radiating element and reflector. By carefully adjusting these parameters, the design achieves the necessary electrical length for the reflector (λ/4) while minimizing the physical package dimensions. The conductive material properties and layer thicknesses are also optimized to maintain performance in a compact configuration.
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 allows for the implementation of millimeter wave atomic clocks in very thin substrates, enhancing operational efficiency and reducing package thickness, suitable for applications like 5G, RADAR, and IoT, without compromising signal coupling or increasing costs.
Implementation Method 1
The mm-wave frequency spectrum lies between microwave and infrared waves with frequencies between about 30 GHz and 300 GHz. An antenna can be used to couple a chip scale gas cell with transceiver circuitry, for example, to transmit a 121 GHz signal from a mm-wave transceiver to the antenna and to launch the same signal from a substrate package to a silicon physics cell
Implementation Method 2
Efficient performance results when the antenna structure provides a coupling reflector at λ/4. The conductive reflector wall has an opening and extends along the third direction between the first and second trace levels around a portion of the conductive coupler antenna
Implementation Method 3
Certain gas molecules (e.g., water or H2O) have defined quantum rotational state transitions, and such molecules absorb energy at a very repeatable frequency when transitioning between rotational states. For example, water absorbs energy based on quantum rotational state transitions around 183 GHz, and other physics cells (e.g., oxygen carbonil sulfide or OCS) have peak absorption around 121 GHz
Data Source
AI summary
A packaged electronic device includes a multilayer lead frame having first and second trace levels, a via level therebetween, a conductive feed structure, and a conductive reflector wall. The first trace level includes a conductive coupler antenna and a conductive ground structure that extends in a plane of orthogonal first and second directions, and a portion of the conductive coupler antenna faces outward along a third direction orthogonal to the first and second directions. The conductive reflector wall has an opening and extends along the third direction between the first and second trace levels around a portion of the conductive coupler antenna. The conductive feed structure is coupled to the conductive coupler antenna and extends along the first direction through the opening of the conductive reflector wall.