High frequency PCB element behaviour

[tretmax]

Hey, i got broken marine radar and checking if i am able to fix it, but before i need to get full picture how it works and i still not fully sure if i got correctly this part of PCB.
Context: pulse radar, working range 9.2-9.4Ghz, pretty high frequency stuff mostly looks like black magic for me.

My guess: once received signal got into antenna we shift it with 90° out of initial phase, next step cascade of 3 amplifiers for each signal(original) and (shifted 90°) and final part we combine amplified signals into 1 that shifted by 90° from original but now significantly amplified.
If it is correct, what idea of this splitting/combining for amplifying, could we get better gain like x2, also what is idea to shift original signal by 90°

Some small questions: those transistors has marking: FQ, EQ, EQ(first signal hit transistor with FQ mark) i have tried to find any of those but without luck maybe some though what it could be ?
Also not fully clear for me what is element that i circled with red, there are multiple of this kind along the micristrip lines, it is something for impedance matching ?

Thank you!

 

[BigBoss]

It's not a Higher Gain, they are for Higher Output Level.
Red Circled element might be a test Connector during Manufacturing.( or Service purpose ).
Silkscreen codes have no universal meaning. You should check the SMD codes on the components if there are.

 

[tretmax]

It's not a Higher Gain, they are for Higher Output Level.

Got this, but not get what is output level in this context, so if reference level before divider is 0 dBm, after divider it will be each -3dBm, if each amplifiers cascade gives signal + 20 dBm, after combiner we will get:

(-3 + 20) + 3 dBm

Red Circled element might be a test Connector during Manufacturing.( or Service purpose ).

this make sense, indeed good catch.

Silkscreen codes have no universal meaning. You should check the SMD codes on the components if there are.

Yeah, here SMD code same as PCB marks, so not really helpful.

 

[BigBoss]

Got this, but not get what is output level in this context, so if reference level before divider is 0 dBm, after divider it will be each -3dBm, if each amplifiers cascade gives signal + 20 dBm, after combiner we will get:

(-3 + 20) + 3 dBm

Yep, this is correct but the last one ( especially ) works in Linear Region by 3dB lower compare to single ended. So, you will get "fictitiously" +3dB Headroom. It's worth, right ?
Additionally,

 

[Yigit Yalcinkaya]

FQ, EQ, and EQ Xtors work like LNA. For this reason, This balanced amplifier has less noise figure and more power according to single amplifiers. And probably, this application has the cheapest cost. Because BW is really short.

it would help if you read Microwave Transistor Amplifiers: Analysis and Design. Pozar, Microwave Engineering has little knowledge about balanced and single amplifiers.