Lateral mode capacitive microphone including a capacitor plate with sandwich structure for ultra high performance

A capacitive microphone comprising a first electrical conductor and a second electrical conductor configured to have a relative spatial relationship therebetween,

• wherein a mutual capacitance (MC) can be generated between the first electrical conductor and the second electrical conductor;
• wherein said relative spatial relationship and said mutual capacitance can both be varied by an acoustic pressure impacting upon the first electrical conductor and/or the second electrical conductor along a range of impacting directions in 3D space;
• wherein said mutual capacitance is varied the most by an acoustic pressure impacting upon the first electrical conductor and/or the second electrical conductor along one direction among said range of impacting directions, said one direction being defined as the primary direction;
• wherein the first electrical conductor has a first projection along said primary direction on a conceptual plane that is perpendicular to said primary direction;
• wherein the second electrical conductor has a second projection along said primary direction on the conceptual plane;
• wherein the first projection and the second projection have a shortest distance Dmin therebetween, and Dmin remains greater than zero regardless of that the first electrical conductor and/or the second electrical conductor is (are) impacted by an acoustic pressure along said primary direction or not;
• wherein one of the two electrical conductors includes an electrical insulator sandwiched between two sub-conductors;
• and said mutual capacitance consists of two sub-capacitances generated between another one of the two electrical conductors and the two sub-conductors, and
• wherein the electrical insulator and the two sub-conductors are stacked over each other along the primary direction, forming a three-layer “sandwich” structure.