A modular reusable AiP radio frequency channel structure based on vertical cross-section impedance anchoring and a design method thereof

Abstract

The application discloses a modular reusable AiP radio frequency channel structure based on vertical cross-section impedance anchoring and a design method thereof. The modular reusable AiP radio frequency channel structure comprises a front-end standardized vertical transition module, a full-coated quasi-coaxial horizontal transmission module and a rear-end antenna feed module, and bidirectional 50-ohm impedance anchoring is implemented on the vertical cross-section of each module cascade. The intermediate layer full-coated quasi-coaxial horizontal transmission module is composed of upper and lower solid ground shielding layers and two side sub-wavelength spacing via walls to form a full-coated cavity, so that the change of the length of the horizontal section only introduces linear phase delay without destroying impedance matching. The application realizes 100% modular reuse of the core vertical interconnection structure in a multi-channel array, shortens the design period from several months to several days, and completely eliminates millimeter wave frequency band radiation leakage and near-field crosstalk.

Description

Technical Field

[0001] This invention belongs to the field of millimeter-wave communication and phased array system technology. Specifically, it relates to an antenna-in-package (AiP) radio frequency channel structure, and more particularly to a modular reusable AiP radio frequency channel structure based on vertical cross-section impedance anchoring and its design method. Background Technology

[0002] With the rapid evolution of millimeter-wave communication and high-frequency phased array systems, antenna-in-package (AiP) technology has become the mainstream architecture due to its high integration and low interconnect loss. In a typical multilayer package substrate, radio frequency signals need to pass through dense vertical interconnect vias and horizontal transmission lines to complete the three-dimensional spatial crossing from the microbumps of the bottom radio frequency chip to the top radiating antenna.

[0003] Existing AiP multi-channel RF links mostly adopt a top-down, end-to-end integrated impedance matching design. Since phased array systems typically contain dozens or even hundreds of RF channels, each with different physical layout coordinates on the substrate, the lengths of horizontal traces within the substrate inevitably vary. Under the traditional design paradigm of strong coupling of end-to-end parameters, any change in the length of the horizontal traces will directly disrupt the electromagnetic boundary conditions of the entire "chip-substrate-antenna" link, leading to severe impedance mismatch.

[0004] This strong coupling characteristic forces designers to perform extremely time-consuming 3D full-wave electromagnetic simulations and iterative optimizations for each channel with different physical spans. This not only makes it extremely difficult to reuse optimized core structures such as vertical interconnects in different channels or projects, resulting in a serious waste of computing resources and a significant delay in the development cycle, but also greatly increases the engineering difficulty of ensuring the consistency of electrical performance across multiple channels in large-scale arrays.

[0005] Therefore, there is an urgent need for a new AiP RF channel architecture that can achieve full-link electrical decoupling, modular reuse of core structures, significantly shorten simulation cycles, and eliminate channel crosstalk. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a modular and reusable AiP RF channel structure and its design method based on vertical cross-section impedance anchoring, in order to overcome the problems of poor design flexibility, non-reusability of core structure, lengthy simulation cycle, and serious crosstalk and radiation leakage in existing AiP multi-channel RF links.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a modular reusable AiP RF channel structure based on vertical cross-sectional impedance anchoring, wherein the RF channel structure is disposed within a multilayer packaging substrate and comprises:

[0009] A standardized vertical transition module at the front end is used to connect to the RF chip;

[0010] The middle layer fully covers the quasi-coaxial horizontal transmission module, and its characteristic impedance is preset to the standard impedance value.

[0011] A standardized back-end antenna feed module is used to feed power to the antenna radiating elements;

[0012] The front-end standardized vertical transition module, the middle layer fully enclosed quasi-coaxial horizontal transmission module, and the back-end standardized antenna feeding module are cascaded sequentially along the signal transmission direction, and bidirectional 50-ohm characteristic impedance anchoring is implemented on the vertical cross section of each cascade.

[0013] Preferably, the intermediate layer fully enclosed quasi-coaxial horizontal transmission module includes:

[0014] The center signal trace is located in the intermediate layer;

[0015] A solid grounding shield layer located above the center signal trace and separated from it by an insulating dielectric layer;

[0016] The lower solid grounding shield layer is located below the center signal trace and separated from it by an insulating dielectric layer;

[0017] Two rows of metallized grounding via walls are arranged on the coplanar grounding copper sheets on the left and right sides of the center signal trace along the extension direction of the center signal trace.

[0018] The two rows of metallized grounding via walls connect upwards to the upper solid grounding shielding layer and downwards to the lower solid grounding shielding layer, thereby forming a fully enclosed quasi-coaxial shielding cavity surrounding the center signal trace.

[0019] Preferably, in the two rows of metallized grounding via walls, the center-to-center distance between two adjacent metallized grounding vias is less than one-tenth of the wavelength corresponding to the highest operating frequency of the system.

[0020] Preferably, the characteristic impedance of the intermediate layer fully enclosed quasi-coaxial horizontal transmission module is determined by the line width W of the center signal trace, the insulation distance S between the center signal trace and the coplanar grounding copper trace, the dielectric thickness H1 between the center signal trace and the upper solid grounding shield, and the dielectric thickness H2 between the center signal trace and the lower solid grounding shield.

[0021] Preferably, the front-end standardized vertical transition module includes a vertical via, anti-pad, and signal conversion structure between the microbumps of the RF chip and the input port of the fully enclosed quasi-coaxial horizontal transmission module in the intermediate layer, and the input and output ports of the vertical transition module are both anchored to a 50-ohm characteristic impedance on the corresponding vertical cross-section.

[0022] Preferably, the back-end standardized antenna feed module includes a vertical via, anti-solder pad, and impedance matching structure from the output port of the middle layer fully enclosed quasi-coaxial horizontal transmission module to the feed point of the antenna radiating element, and the input port and output port of the antenna feed module are both anchored to a 50-ohm characteristic impedance on the corresponding vertical cross-section.

[0023] Secondly, the present invention provides a multi-channel phased array antenna system based on the above-mentioned modular reusable AiP RF channel structure, comprising multiple RF channels, each RF channel adopting the same front-end standardized vertical transition module and the same back-end standardized antenna feed module, the intermediate layer fully enclosed quasi-coaxial horizontal transmission module of each RF channel having the same or different physical lengths, and the horizontal transmission modules of different physical lengths can be directly replaced by the system without disrupting the 50-ohm impedance matching state of the entire link.

[0024] Thirdly, the present invention provides a design method for the above-mentioned radio frequency channel structure, characterized by comprising the following steps:

[0025] The entire RF path is divided into a front-end standardized vertical transition module, a middle-layer fully enclosed quasi-coaxial horizontal transmission module, and a back-end standardized antenna feeding module.

[0026] Through full-wave electromagnetic simulation or parameter scanning, the front-end standardized vertical transition module, the middle layer fully enclosed quasi-coaxial horizontal transmission module, and the back-end standardized antenna feeding module were optimized independently, so that each module achieved a characteristic impedance of 50 ohms on the vertical cross-section of its input and output ports.

[0027] The optimized front-end standardized vertical transition module, the middle layer fully enclosed quasi-coaxial horizontal transmission module, and the back-end standardized antenna feeding module are cascaded in sequence to form a complete radio frequency channel;

[0028] In the multi-channel array design, the structure and size of the standardized front-end vertical transition module and the standardized back-end antenna feed module remain unchanged. Only the trace length of the intermediate layer fully enclosed quasi-coaxial horizontal transmission module is changed according to the physical span from the chip to the antenna to complete the design of all RF channels.

[0029] In the method of this invention, when optimizing the intermediate layer fully enclosed quasi-coaxial horizontal transmission module, its cross-sectional dimensions (center signal trace width W, insulation spacing S, upper and lower dielectric thicknesses H1 and H2) are fixed, so that the characteristic impedance per unit length of the module is constant at 50 ohms. Therefore, changes in its physical length only introduce linear phase delay without causing impedance mismatch reflection. When it is necessary to change the physical length of the intermediate layer horizontal transmission module of a certain RF channel, there is no need to re-optimize the front-end or back-end modules using any three-dimensional full-wave electromagnetic simulation. The channel reconfiguration is achieved directly by changing the wiring length of the horizontal transmission module or its equivalent electrical length.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] This invention decomposes a highly coupled and complex RF link into three standardized sub-modules—front-end, middle, and back-end—by constructing a fully enclosed quasi-coaxial shielded transmission line (intermediate layer fully enclosed quasi-coaxial horizontal transmission module) with a standard 50-ohm characteristic impedance inside the substrate and implementing bidirectional impedance anchoring at the vertical cross-section where it intersects with the front and rear vertical interconnect structures. When the physical length of the horizontal channel is changed, only a linear phase delay is introduced, without disrupting the impedance matching state at the beginning and end, allowing the core vertical interconnect structure to be plug-and-play and 100% reused in all channels. Therefore, only one standard structure needs to be designed, and the entire array design can be completed simply by changing the length of the horizontal trace, without the need for repeated three-dimensional simulations for each channel. Compared to existing technologies, the design cycle for multi-channel phased arrays can be shortened from months to days, significantly improving R&D efficiency and reducing computational resource consumption.

[0032] Furthermore, this invention utilizes the "Faraday cage" shielding effect of a fully enclosed quasi-coaxial cavity transmission line to force high-frequency signals to transmit in a pure quasi-TEM mode with low loss, constructing a "physical zero-field region" around the transmission line. In millimeter-wave bands and high-density parallel wiring environments, it can suppress near-field crosstalk between adjacent channels to below -35 dB, and the channel isolation is significantly better than that of traditional microstrip lines or coplanar waveguide structures (typically only -18 to -22 dB), thus providing ultimate channel isolation and signal integrity guarantees for large-scale phased array systems. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0034] Figure 2 This is a schematic diagram of the structure of a quasi-coaxial horizontal transmission module with full coverage in the middle layer.

[0035] Figure 3 This is a model diagram of a fully enclosed quasi-coaxial horizontal transmission module in the middle layer.

[0036] Figure 4The S(2,2) parameter curve of the 140GHz single-channel radio frequency channel constructed for Example 1.

[0037] Figure 5 , Figure 6 , Figure 7 The figures show the S(2,2) parameter curves obtained by different conventional matching design methods. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] like Figure 1 As shown, the present invention provides a modular reusable AiP RF channel structure based on vertical cross-section impedance anchoring. The RF channel structure is disposed in a multilayer package substrate and includes a front-end standardized vertical transition module, a middle layer fully enclosed quasi-coaxial horizontal transmission module, and a back-end standardized antenna feeding module. The three are cascaded sequentially along the signal transmission direction, and bidirectional 50-ohm characteristic impedance anchoring is implemented on the vertical cross-section of each cascade.

[0040] Specifically, the front-end standardized vertical transition module is used to connect to the radio frequency chip, including: a vertical via, anti-pad and signal conversion structure between the micro-bumps of the radio frequency chip and the input port of the fully enclosed quasi-coaxial horizontal transmission module in the middle layer, and the input port and output port of the vertical transition module are both anchored to a 50-ohm characteristic impedance on the corresponding vertical cross section.

[0041] The characteristic impedance of the intermediate layer fully enclosed quasi-coaxial horizontal transmission module is preset to a standard impedance value; such as Figure 2 As shown, it includes: a center signal trace located in the middle layer; an upper solid grounding shield layer located above the center signal trace and separated from it by an insulating dielectric layer; a lower solid grounding shield layer located below the center signal trace and separated from it by an insulating dielectric layer; and two rows of metallized grounding via walls arranged on coplanar grounding copper sheets on the left and right sides of the center signal trace along its extension direction. The two rows of metallized grounding via walls are connected upwards to the upper solid grounding shield layer and downwards to the lower solid grounding shield layer, thereby forming a structure surrounding the center. The signal trace is fully enclosed in a quasi-coaxial shielded cavity; in the two rows of metallized grounding via walls, the center-to-center distance between two adjacent metallized grounding vias is less than one-tenth of the wavelength corresponding to the highest operating frequency of the system; the characteristic impedance of the intermediate layer fully enclosed quasi-coaxial horizontal transmission module is determined by the linewidth W of the center signal trace, the insulation distance S between the center signal trace and the coplanar grounding copper foil of the same layer, the dielectric thickness H1 between the center signal trace and the upper solid grounding shield layer, and the dielectric thickness H2 between the center signal trace and the lower solid grounding shield layer.

[0042] The standardized antenna feed module at the back end is used to feed the antenna radiating element. It includes a vertical via, anti-solder pad and impedance matching structure from the output port of the fully enclosed quasi-coaxial horizontal transmission module in the middle layer to the feed point of the antenna radiating element. The input port and output port of the antenna feed module are both anchored to a 50-ohm characteristic impedance on the corresponding vertical cross section.

[0043] Example 1: 140GHz band single-channel AiP RF channel structure

[0044] (1) Substrate stack-up structure and material parameters

[0045] This embodiment uses an 8-layer organic packaging substrate, with each layer made of copper as the metal material and Mitsubishi HL972LF as the dielectric material, which has a relative permittivity of 3.4 and a loss tangent of 0.004. The dielectric thickness between layers is 0.06 mm. The total substrate thickness is approximately 0.48 mm (excluding the surface solder mask).

[0046] (2) Front-end standardized vertical transition module

[0047] The front-end standardized vertical transition module is used to bring the differential RF signals of the RF chip out from the bottom BGA pads to the input port of the middle layer horizontal transmission module.

[0048] The vertical via adopts a cylindrical structure with a diameter of 0.06 mm. An anti-pad, circular in shape with a diameter of 0.14 mm, is placed on the ground plane surrounding the via. The ratio of the anti-pad diameter to the signal via diameter is 2.33, and this ratio is strictly controlled within the preferred range of 2.0 to 3.5. Full-wave electromagnetic simulation has verified that this ratio effectively balances the parasitic inductance and capacitance to ground of the via, enabling precise anchoring of the vertical transition module to a 50-ohm characteristic impedance on both the input and output ports.

[0049] (3) Intermediate layer fully enclosed quasi-coaxial horizontal transmission module

[0050] This embodiment uses the 5th metal layer (LM5 layer) as the core signal layer to construct a fully enclosed quasi-coaxial horizontal transmission module, which connects the front-end standardized vertical transition module and the back-end antenna feeding module. The specific structural parameters of this module are as follows:

[0051] The center signal trace width W was determined to be 0.041mm after simulation optimization.

[0052] The insulation distance S between the center signal trace and the coplanar grounding copper trace on the same layer is 0.03mm;

[0053] The dielectric thickness H1 between the center signal trace and the upper solid grounding shield is 0.06mm (corresponding to LM4 to LM5 layers).

[0054] The dielectric thickness H2 between the center signal trace and the lower solid ground shield is 0.06mm (corresponding to LM5 to LM6 layers).

[0055] The upper solid grounding shield is set on the LM4 layer, and the lower solid grounding shield is set on the LM6 layer. Both layers are fully copper-clad without any ribbon cable openings.

[0056] Along the direction of the central signal trace, a row of metallized grounding vias is arranged on the coplanar grounding copper foil on both sides, forming two rows of via walls. The via diameter is 0.06mm, and the center-to-center spacing between adjacent vias is 0.12mm. The free-space wavelength corresponding to the 140GHz band is λ≈2.14mm, λ / 10≈0.214mm. In this embodiment, the center-to-center spacing between adjacent vias is less than 0.214mm, satisfying the constraint condition of "subwavelength spacing". This spacing ensures that the discrete via walls form a continuous and dense metal wall under the equivalent electromagnetic wave perspective, effectively preventing high-frequency signals from leaking outward.

[0057] By coordinating the above-mentioned size parameters (W=0.041mm, S=0.03mm, H1=0.06mm, H2=0.06mm), the intermediate layer horizontal transmission module of this embodiment achieves a characteristic impedance of precisely 50 ohms in the 140GHz target frequency band.

[0058] (4) Standardized antenna feed module at the back end

[0059] The structure of the back-end antenna feed module is basically symmetrical to that of the front-end standardized vertical transition module. It uses the same specifications of vertical via (0.06mm in diameter) and anti-solder pad (0.14mm in diameter) to boost the signal from the LM5 layer to the LM8 layer (antenna feed layer), and also achieves 50-ohm characteristic impedance anchoring on the vertical cross-section of the output port.

[0060] (5) Method for achieving 50-ohm vertical section anchorage

[0061] In this embodiment, bidirectional 50-ohm characteristic impedance anchoring was achieved at four key vertical sections: the output port of the front-end standardized vertical transition module, the input and output ports of the intermediate layer horizontal transmission module, and the input port of the rear-end antenna feed module, through the aforementioned parameter settings and simulation verification. The specific process is as follows:

[0062] S1. Independently optimize the front-end standardized vertical transition module, adjust the ratio of via diameter to antipad diameter (controlled within the range of 2.0~3.5), so that its input / output ports are matched to 50 ohms;

[0063] S2. Independently optimize the intermediate layer horizontal transmission module, fix the four cross-sectional dimensions of W, S, H1, and H2, and make its characteristic impedance per unit length 50 ohms;

[0064] S3. Independently optimize the back-end antenna feed module, adopting the same via / anti-pad design rules as the front end, so that its input port is matched to 50 ohms;

[0065] S4. Cascade the three modules in sequence. Since the impedance of each module at the cascade cross section is 50 ohms, the impedance of the entire link will be naturally matched after cascading, and no joint iterative optimization is required.

[0066] (6) Performance verification and beneficial effects

[0067] To verify the transmission performance of the RF channel structure described in this embodiment, S-parameter simulation analysis was performed on the entire link. Figure 4 The figure shows the S(2,2) parameter curve of a 140GHz single-channel RF channel constructed using the design method of this embodiment. Figure 4 As can be seen, the curve exhibits a sharp deep resonance characteristic near the target frequency band of 140GHz, with a reflection coefficient as low as approximately -45dB at the 140GHz center frequency. Within the operating frequency band from 135GHz to 145GHz, the reflection coefficient remains below -20dB, and good symmetry is observed on both sides of 140GHz. These results demonstrate that this embodiment, through the coordinated design of the front-end vertical transition module, the intermediate layer quasi-coaxial horizontal transmission module, and the back-end antenna feeding module, as well as the precise anchoring of the 50-ohm characteristic impedance on four key vertical sections, achieves deep impedance matching across the entire link in the 140GHz target frequency band, resulting in minimal signal reflection and extremely high transmission efficiency.

[0068] In contrast. Figures 5 to 7 The S(2,2) parameter curves obtained using other conventional matching design methods are shown. Figure 5 The reflection coefficient is approximately -18.2 dB at 135 GHz, deteriorates to approximately -13.9 dB at 145 GHz, and reaches its lowest point at approximately 133 GHz, which is not aligned with the target frequency band. Figure 6 The matching depth is insufficient throughout the 135-145GHz band, with the lowest point being only about -17.5dB and deviating to around 130GHz. At 145GHz, the reflection coefficient is only -10.2dB. Figure 7 Although a reflection coefficient of approximately -28 dB was achieved at the lowest point, its resonant frequency was located at approximately 133 GHz, deviating from the target frequency band by 7 GHz, and it also deteriorated to -10.2 dB at 145 GHz. The above comparative results clearly demonstrate that... Figures 5 to 7The conventional design method shown may have problems such as the resonant point deviating from the target frequency band, insufficient in-band matching depth, and deterioration of high-frequency performance, either because it does not consider the impedance continuity of the vertical cross section of the entire link or because it lacks a modular 50-ohm anchoring strategy.

[0069] Figure 5 This corresponds to the traditional "top-down" end-to-end integrated impedance-controlled matching structure. The essential characteristic of this structure is that it does not physically and electrically separate the RF path into a front-end vertical transition module, an intermediate horizontal transmission module, and a back-end antenna feeding module; the entire RF path is treated as an indivisible, strongly coupled whole system. Under this structure, due to the lack of an electrical decoupling mechanism, when the horizontal trace length changes due to differences in the physical layout of the channel within the phased array, the electromagnetic boundary conditions of the entire link will drift as a whole. For example... Figure 5 As shown in the simulation curves, its resonant point deviates significantly from the 140GHz center frequency (the lowest point deviates to approximately 133GHz), and the reflection coefficient deteriorates to approximately -13.9dB at the 145GHz high-frequency end. This is precisely because the overall distributed parameter distortion caused by the change in trace length cannot be absorbed internally, leading to the complete failure of the end-to-end integrated matching network.

[0070] Figure 6 This corresponds to an RF channel structure that, while formally divided into vertical and horizontal segments, lacks impedance anchoring. The essential characteristic of this structure is that, although the channel is physically divided into different segments, the characteristic impedance is not forcibly calibrated and locked to a standard 50 ohms at the vertical cross-section of the cascaded modules through parameter coordination. Because the equivalent input impedance at the cascaded cross-section is in an uncalibrated and variable state (usually complex or non-standard impedance), severe impedance steps and discontinuities occur at the vertical cascaded cross-section when these modules are networked and cascaded in three-dimensional space. For example... Figure 6 The simulation curves show that its in-band matching depth is severely insufficient, with the lowest point being only about -17.5dB and deviating to around 130GHz. At 145GHz, the return loss is only -10.2dB. This drastic distortion in electromagnetic performance is due to the lack of vertical 50-ohm impedance anchoring, which leads to strong multiple microwave standing wave reflections excited by parasitic abrupt changes at the cascaded cross-section.

[0071] Figure 7This corresponds to the RF channel in which the intermediate horizontal transmission section adopts a traditional semi-open planar structure, i.e., a coplanar waveguide. The essential characteristic of this structure is that it lacks the fully enclosed quasi-coaxial shielding cavity formed by the "top and bottom solid grounding shielding layers" and "side subwavelength-spacing metallized via walls" of this invention on both sides and above and below the horizontal traces of the intermediate layer. At extremely high frequencies such as 140GHz, the edge field divergence and lateral leakage effects of this semi-open planar structure are extremely detrimental, causing severe radiation leakage of high-frequency signals during transmission. For example... Figure 7 As shown in the simulation curves, due to the lack of electromagnetic confinement from a fully shielded structure, energy dissipation disrupts the transmission line impedance reference, resulting in a drastic shift in the resonant frequency of up to 7 GHz (deviating to 133 GHz), and a sharp deterioration in the reflection coefficient at the high-frequency end (145 GHz) to -10.2 dB. In multi-channel dense cabling environments, this structure will also cause severe inter-channel near-field crosstalk due to spatial leakage, failing to meet the amplitude and phase consistency requirements of large-scale arrays.

[0072] Example 2: 100GHz band single-channel AiP RF channel structure

[0073] This embodiment uses the same 8-layer substrate structure, the same material parameters (Mitsubishi HL972LF, dielectric constant 3.4), the same interlayer dielectric thickness (0.06mm), the same vertical via parameters (diameter 0.06mm), and the same anti-pad parameters (diameter 0.14mm) as Embodiment 1.

[0074] The difference lies in the fact that, due to the reduced operating frequency to 100GHz, the center signal trace width W was adjusted through simulation optimization to achieve a 50-ohm characteristic impedance for the intermediate layer horizontal transmission module. The specific parameters are as follows:

[0075] Center signal trace width W: 0.0342mm;

[0076] Insulation spacing S: 0.03 mm (consistent with Example 1);

[0077] The thicknesses of the upper and lower media, H1 and H2, are 0.06 mm (consistent with Example 1).

[0078] Example 3: 50GHz band single-channel AiP RF channel structure

[0079] This embodiment uses the same substrate structure and material parameters as the previous embodiments. To achieve 50-ohm impedance matching in the 50GHz band, the key dimensions of the intermediate layer horizontal transmission module were obtained through simulation optimization as follows:

[0080] Center signal trace width W: 0.0287mm;

[0081] Insulation spacing S: 0.03mm (consistent with the aforementioned embodiment);

[0082] The thicknesses of the upper and lower media, H1 and H2, are 0.06 mm (consistent with the aforementioned embodiment).

Claims

1. A modular, reusable AiP RF channel structure based on vertical cross-section impedance anchoring, characterized in that, The radio frequency channel structure is disposed within a multilayer packaging substrate and includes: A standardized vertical transition module at the front end is used to connect to the RF chip; The middle layer fully covers the quasi-coaxial horizontal transmission module, and its characteristic impedance is preset to the standard impedance value. A standardized back-end antenna feed module is used to feed power to the antenna radiating elements; The front-end standardized vertical transition module, the middle layer fully enclosed quasi-coaxial horizontal transmission module, and the back-end standardized antenna feeding module are cascaded sequentially along the signal transmission direction, and bidirectional 50-ohm characteristic impedance anchoring is implemented on the vertical cross section of each cascade.

2. The modular reusable AiP RF channel structure based on vertical cross-section impedance anchoring according to claim 1, characterized in that, The intermediate layer fully enclosed quasi-coaxial horizontal transmission module includes: The center signal trace is located in the intermediate layer; A solid grounding shield layer located above the center signal trace and separated from it by an insulating dielectric layer; The lower solid grounding shield layer is located below the center signal trace and separated from it by an insulating dielectric layer; Two rows of metallized grounding via walls are arranged on the coplanar grounding copper sheets on the left and right sides of the center signal trace along the extension direction of the center signal trace. The two rows of metallized grounding via walls connect upwards to the upper solid grounding shielding layer and downwards to the lower solid grounding shielding layer, thereby forming a fully enclosed quasi-coaxial shielding cavity surrounding the center signal trace.

3. The modular reusable AiP RF channel structure based on vertical cross-section impedance anchoring according to claim 2, characterized in that, In the two rows of metallized grounding via walls, the center-to-center distance between two adjacent metallized grounding vias is less than one-tenth of the wavelength corresponding to the highest operating frequency of the system.

4. The modular reusable AiP RF channel structure based on vertical cross-section impedance anchoring according to claim 2, characterized in that, The characteristic impedance of the intermediate layer fully enclosed quasi-coaxial horizontal transmission module is determined by the line width W of the center signal trace, the insulation distance S between the center signal trace and the coplanar grounding copper trace, the dielectric thickness H1 between the center signal trace and the upper solid grounding shield, and the dielectric thickness H2 between the center signal trace and the lower solid grounding shield.

5. The modular reusable AiP RF channel structure based on vertical cross-section impedance anchoring according to claim 1, characterized in that, The front-end standardized vertical transition module includes vertical vias, anti-pads, and signal conversion structures between the micro-bumps of the RF chip and the input port of the fully enclosed quasi-coaxial horizontal transmission module in the intermediate layer. The input and output ports of the vertical transition module are both anchored to a 50-ohm characteristic impedance on their corresponding vertical cross-sections.

6. The modular reusable AiP RF channel structure based on vertical cross-section impedance anchoring according to claim 1, characterized in that, The back-end standardized antenna feed module includes a vertical via, anti-solder pad, and impedance matching structure from the output port of the middle layer fully enclosed quasi-coaxial horizontal transmission module to the feed point of the antenna radiating element. The input and output ports of the antenna feed module are both anchored to a 50-ohm characteristic impedance on the corresponding vertical cross-section.

7. A multi-channel phased array antenna system based on the modular reusable AiP RF channel structure described in any one of claims 1-6, characterized in that, It includes multiple radio frequency channels, each of which uses the same front-end standardized vertical transition module and the same back-end standardized antenna feed module. The intermediate layer fully enclosed quasi-coaxial horizontal transmission module of each radio frequency channel has the same or different physical lengths, and the horizontal transmission modules of different physical lengths can directly replace the access system without disrupting the 50-ohm impedance matching state of the entire link.

8. A design method for a modular reusable AiP RF channel structure as described in any one of claims 1-6, characterized in that, Includes the following steps: The entire RF path is divided into a front-end standardized vertical transition module, a middle-layer fully enclosed quasi-coaxial horizontal transmission module, and a back-end standardized antenna feeding module. Through full-wave electromagnetic simulation or parameter scanning, the front-end standardized vertical transition module, the middle layer fully enclosed quasi-coaxial horizontal transmission module, and the back-end standardized antenna feeding module were optimized independently, so that each module achieved a characteristic impedance of 50 ohms on the vertical cross-section of its input and output ports. The optimized front-end standardized vertical transition module, the middle layer fully enclosed quasi-coaxial horizontal transmission module, and the back-end standardized antenna feeding module are cascaded in sequence to form a complete radio frequency channel; In the multi-channel array design, the structure and size of the standardized front-end vertical transition module and the standardized back-end antenna feed module remain unchanged. Only the trace length of the intermediate layer fully enclosed quasi-coaxial horizontal transmission module is changed according to the physical span from the chip to the antenna to complete the design of all RF channels.

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