Four broadband RF grounding capacitor array are designed, implemented, and compared with different maximum path loss and parasitic for CMOS broadband amplifiers. According to the measured results, the most popular RF grounding capacitor array with simple parallel connected topology is not suitable for broadband circuits because of its loss at high frequency. The other three proposed topologies with reduction of path losses and parasitic have better broadband characteristics than the simple parallel connected type. To understand the effect of RF grounding capacitor array in broadband circuits, the type II capacitor array is adopted in the experiment circuit, a matrix distributed amplifier, and the measured result shows well-estimation could be obtained with the consideration of grounding capacitors. This 2 × 2 matrix amplifier achieves a better gain-bandwidth product versus power consumption among recent CMOS broadband amplifier designs.