Re: explanation of circuit
vhf choke's function is to prevent rf signal influences dc bias circuit so as minimum as possible rf signal power dissipates in dc bias circuit.
C1 and C5 r coupling capacitors, aimed to prevent dc signal (bias) from previous stage enters the stage and dc signal at current stage enters next stage.
L1-C2-C3 and L2-C4 are transistor's matching impedances
Dr1, Dr3, Dr2 r VHF choke
R1 : bias resistance
D1 : voltage regulator, to minimize effect of powersupply's ripple on transistor base's bias
C6 : decoupling capacitor