Determining Antenna Separation Requirements for Co-Located Transmitters
Minimum antenna separation depends on transmitter power, receiver blocking thresholds, intermodulation mixing products, and regulatory simultaneous exposure ratios.
1db Compression Point
Meaning
Radio frequency amplification performance relies on a threshold where output power diverges from the linear output of the circuit. The 1db compression point defines this boundary, indicating where the gain of the amplifier drops by one decibel. Above this power level, the active device begins to saturate, causing distortion.
Power Limitation
Design requirements for active electronic components specify this limit to prevent severe harmonic generation. Operating an amplifier too close to the 1db compression point causes unwanted intermodulation products that interfere with adjacent frequency channels. This behavior is crucial when integrating a wireless transceiver onto a dense system board where multiple antennas operate simultaneously.
Designers usually maintain a backoff of several decibels to ensure linear performance. High peak-to-average power ratio signals require this margin to prevent clipping and spectral regrowth.
System Distortion
Bit error rate degrades rapidly when the signal peaks enter the saturation region of the transmitter. Linear modulation schemes rely on amplitude and phase variations, which are easily corrupted by gain compression. In a modular wireless assembly, the 1db compression point of the power amplifier dictates the maximum safe output level for the entire system.
Handover documents often specify this value to set the baseline for compliance testing.
Acceptance Criterion
Production testing locates the compression knee by measuring output power against input power. If the module reaches the 1db compression point too early, the unit is rejected. This check secures final product quality.