Single-sided printed circuit boards (PCBs) are widely used in various electronic devices due to their simplicity and cost-effectiveness. However, they are more vulnerable to electromagnetic interference (EMI) compared to multi-layer boards. Effective anti-interference design methods are crucial to ensure the reliable operation of electronic circuits on single-sided PCBs.

　　One of the fundamental anti-interference design strategies is proper layout planning. The placement of components and traces on the PCB significantly impacts its susceptibility to interference. Digital and analog components should be separated as much as possible. Digital circuits generate high-frequency signals that can easily interfere with sensitive analog circuits. By keeping them apart, the risk of crosstalk is reduced. For example, in a simple audio amplifier circuit on a single-sided PCB, the audio input and output stages (analog components) should be located away from the microcontroller or digital control sections. Additionally, high-speed signal traces should be kept short and straight to minimize electromagnetic radiation. Sharp bends in traces can act as antennas, radiating unwanted electromagnetic waves.

　　Grounding is another key aspect of anti-interference design for single-sided PCBs. A well-designed ground plane helps in reducing noise and interference. On a single-sided PCB, creating a continuous ground trace around the perimeter of the board can serve as a basic ground plane. All components should be connected to this ground trace with short and low-impedance connections. In more complex designs, ground vias can be used to connect the ground trace on the single-sided board to other metal parts or external grounding points. This helps in dissipating any induced currents and reducing the potential for interference. For instance, in a wireless sensor node using a single-sided PCB, proper grounding ensures that the radio frequency (RF) signals are not distorted by internal electrical noise.

　　Shielding techniques can also be employed to enhance the anti-interference capabilities of single-sided PCBs. Conductive shielding materials, such as copper foil or metal enclosures, can be used to enclose sensitive components or sections of the PCB. The shielding material should be properly grounded to be effective. For example, in a PCB-based radio receiver, shielding the RF front-end circuitry can prevent external electromagnetic signals from interfering with the weak incoming signals. Moreover, ferrite beads can be inserted in power supply lines to suppress high-frequency noise. These beads act as high-frequency resistors, attenuating unwanted signals while allowing the normal low-frequency power supply to pass through. By combining these layout, grounding, shielding, and filtering techniques, single-sided PCBs can be designed to have improved resistance to electromagnetic interference, ensuring stable and reliable operation of the electronic circuits.