The resonance frequency that occurs is dependent on the length of the ground return path. If the wavelength “λ” is long, the resonance frequency occurs in the low frequency band. Conversely, if the wavelength “λ” is short, the resonance frequency occurs in the high frequency band. Figure 3 shows the structure of the mating condition of the plug and receptacle of conventional micro- coaxial connector products. Due to the structure of the connector, the ground path cannot be easily set. Cable and terminal ground paths are connected by ground fingers. The area in green indicates the resonance area.
appearance of a micro-coaxial harness with paddle card. Mating contacts (pads) are configured on the paddle card.
Figure 4: Existing micro- coaxial product
Figure 5: Paddle card product
Figure 6 shows the structure of the mating condition of the plug and receptacle of the paddle card product. It is possible to set up many ground paths through the paddle card (FPC), giving it greater design flexibility.
The area in green indicates the resonance area.
Figure 3: Cross-section of existing product
THE COUNTERMEASURES By replacing the existing plug connector with a paddle card (FPC), the ground path can be easily installed. This leads to a stronger ground path and a shorter resonance area. WHAT IS A PADDLE CARD? A paddle card can be mated with a mating connector, and PCB or FPC can be designed for the plug circuit. Paddle cards are easy to add to ground structures, improving ground return. Impedance matching is simplified, and signal integrity is improved at higher frequencies.
Figure 6: Cross-section of paddle card product
By using a paddle card, the signal line width can be adjusted to specific requirements and the characteristic impedance can be easily matched.
Figure 7 shows a micro-coaxial cable connected to a paddle card. The connection method between the paddle card and the cable is achieved by soldering. The width of the paddle card terminal must be wide for mating contact with the receptacle. The terminals can be narrower at non-contact areas to support characteristic impedance control.
Figure 4 shows the appearance of a conventional micro-coaxial harness. Figure 5 shows the
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