Dual band frequency selective radiator array

1. A dual band frequency selective radiator array for transmitting and receiving radar signals comprising:

a high band radiator array disposed on a dielectric layer for transmitting and receiving high band radar signals;

a low band radiator array disposed on a front side of the high band radiator array for transmitting and receiving low band radar signals;

a frequency selective surface (FSS) tuned to the high band radar signals forming a surface of the low band radiator array that passes the high band radar signals to the high band radiator array; and

a single aperture disposed in front of the low band radiator array, the high band radiator array and the FSS for both the low band radiator array and the high band radiator array for transmitting and receiving the radar signals, wherein

the low band radiator array includes a plurality of tuning stubs tuned to high band frequencies to make the low band radiator array transparent to the high band radiator array.

2. The dual band frequency selective radiator array of claim 1 , wherein the FSS is disposed on the front surface of the low band radiator array.

3. The dual band frequency selective radiator array of claim 1 , wherein the high band radiator array is an array of patched high band radiators.

4. The dual band frequency selective radiator array of claim 1 , wherein the low band radiator array is an array of patch low band radiators.

5. A dual band frequency selective radiator array for transmitting and receiving radar signals comprising:

a high band radiator array disposed on a dielectric layer for transmitting and receiving high band radar signals;

a low band radiator array disposed on a front side of the high band radiator array for transmitting and receiving low band radar signals;

a frequency selective surface (FSS) tuned to the high band radar signals forming a surface of the low band radiator array and passes the high band radar signals to the high band radiator array;

a single aperture disposed in front of the low band radiator array, the high band radiator array and the FSS for both the low band radiator array and the high band radiator array for transmitting and receiving the radar signals; and

a plurality of support ribs to provide support and excitation for the low band radiator array.

6. The dual band frequency selective radiator array of claim 5 , wherein one or more of the support ribs accommodate wires therein to provide current to drive the low band radiator array.

7. The dual band frequency selective radiator array of claim 5 , wherein the support ribs include chokes tuned to high band frequencies to make the support ribs transparent to the high band radiator array.

8. The dual band frequency selective radiator array of claim 5 , wherein the chokes are alternating and each alternate choke is a mirror image of its adjacent choke.

9. The dual band frequency selective radiator array of claim 1 , further comprising a foam formed in a space between the low band radiator array and the high band radiator array to provide a support structure.

10. The dual band frequency selective radiator array of claim 1 , wherein the low band radiator array comprises:

top radiator metal patches formed and spaced apart on a dielectric substrate;

bottom radiator metal patches formed and spaced apart on the dielectric substrate; and

a metal ground plane including openings formed in the dielectric substrate, wherein a spacing of the top radiator patches and a spacing of the bottom radiator patches are aligned with each other, and wherein each opening covers entire spacings of corresponding top and bottom radiator patches.

11. The dual band frequency selective radiator array of claim 1 , wherein the FSS behaves as a metal film at low band frequencies so that the low band radiators do not interfere with high frequency transmit or receive radar signals.