What is the gain of a booster antenn☆☆a? That is to say, und↓★&er the condition of equal input power, the ra♣÷↕tio of the power density o≥✔•≥f the signal generated by the antenna and thδ$σ®e ideal radiating unit at the sam₽‍‌γe point in space. Of course, this expΩ♥Ω♥lanation is a bit confusing. In layman's t®★★erms, gain indicates how many times¶σ& the antenna can amplify the ≤♥signal. Here comes the probφ∑lem again. The booster antenna is a®♦© passive component that does not require poweγ∑★r. How can it be amplified? Isnφ §∞’t this a violation of t₽★© he most basic principle of conservation of ene‍×≈rgy?

Of course, there are many ways of gaining ÷×antennas to achieve high gains. Here we talk abo× ut the gain principle of rod antennas commonly¥‍₽• used in routing. The scientific name of this k맶ind of antenna is call♥σed a spiral inverter antenna. From ♠÷‍βa structural point of view, it is↑€$♥ a hybrid structure of a li♠β∞near oscillator and a spiral inverter. The ↕₩₹§linear oscillator part is responsi$£✔§ble for transmitting the sig®λ≈nal, and the spiral inverter is responsible for <σ¶≥changing the phase of the signalα♠, so that the two oscil↔®lators emit signals with different phases. Af→‌ ter this signal is combined,™∑× a signal with a larger amplitude is£∏∏£ formed. In this way, The signal is enhanced.

However, after the signal δ÷is combined, the radiatioγ↑¥​n angle of the beam will become ₹β↑ smaller. As a rod antenna,β↔ although the radial si≈'φ•gnal is still covered by 360 degrees •, the axial coverage angle is greatly reduced¥<★. That is to say, th↑↓α✔e coverage of the rod-shaped high-gain &"×£antenna does not chang€®∞Ωe. (In fact, after multiple phase invers‍↔↕↑ions and attenuation÷±s, the attenuation of the☆€• signal on the antenna will reducβ→₹<e its transmission function). This is the p'≈<rinciple of energy conservation≠×✔'. Decided, but it is equival↔ →ent to thinning the entire sig♦→nal. In this way, the signal coverag ↓∏e is increased, but the•→ coverage height is red≠¶φuced.