RADAR
A radar receiver having an antenna. The antenna has an array of antenna elements. The receiver also includes a number of processing stages including a first processing stage adapted to process radar signals received via each antenna element of the array and a second processing stage adapted to serve the first processing stage. The processing stages are each arranged substantially parallel to one another, and to the antenna substrate.
1 . A radar receiver, the receiver comprising;
at least one antenna comprising an array of antenna elements;
a first processing stage adapted to process radar signals received via each antenna element of said array; and
a second processing stage adapted to serve the first processing stage;
wherein said first and second processing stages are each arranged substantially parallel to one another, and to said antenna substrate.
2 . A radar receiver, according to claim 1 wherein:
said array of antenna elements are arranged in a plurality of groups (e.g. sub-arrays);
said first processing stage comprises a plurality of processing modules, each processing module being adapted to process radar signals received by a different said group of antenna elements of said array; and
said second processing stage comprises at least one processing module, the or each processing module being adapted to serve at least one (preferably a plurality) of said processing modules of the first processing stage.
3 . A radar receiver according to claim 1 wherein the radar receiver further comprises means for providing a common calibration signal to each said antenna element; wherein said calibration means comprises a plurality of couplers; and wherein each coupler is arranged for coupling to a respective antenna element whereby to provide said calibration signal.
4 . A radar receiver according to claim 1 wherein the at least one antenna is arranged in a plurality of groups, wherein each group comprises a plurality of antenna elements; and wherein the first processing stage comprises a plurality of processing modules, each processing module being adapted to process radar signals received by a different said group of antenna elements.
5 . A radar receiver according to claim 4 wherein the second processing stage comprises at least one processing module, the or each processing module being adapted to serve at least one, preferably a plurality, of said processing modules of the first processing stage.
6 . A radar receiver according to claim 2 wherein the or each processing module of the second processing stage is adapted to serve a plurality of said processing modules of the first processing stage by providing a timing and/or control signal to each said processing module of the first processing stage.
7 . A radar receiver according to claim 6 wherein said timing and/or control signal is provided to each said processing module of the first processing stage via a different respective connection, each said connection having substantially equal path length to each other said connection.
8 . A radar receiver according to claim 2 wherein the or each processing module of the second processing stage is positioned substantially centrally relative to said plurality of processing modules which it serves.
9 . A radar receiver according to claim 2 wherein the or each module of said second processing stage is adapted to serve N modules of the first processing stage wherein N is an integer power of 2, preferably an integer power of 4, advantageously 4.
10 . A radar receiver according to claim 2 wherein the or each module of said first processing stage is adapted to process radar signals received by a group comprising M antenna elements wherein M is an integer power of 2, preferably an integer power of 4, and more preferably 4.
11 . A radar receiver according to claim 9 wherein:
(a) the first processing stage comprises at least four first stage processing modules each of which serves at least four antenna elements; and
(b) the second processing stage comprises at least four second stage processing modules each of which serves at least four first stage processing modules and 16 antenna elements.
12 . A radar receiver according to claim 11 comprising a further processing stage the further processing stage being adapted to serve at least four second stage processing modules and 64 antenna elements.
13 . A radar receiver according to claim 3 wherein said calibration means is adapted to provide a common calibration signal comprising at least one of: a pre-determined amplitude, a pre-determined frequency, a predetermined delay; and/or a pre-determined phase.
14 . A radar receiver according to claim 3 wherein said calibration means comprises a feed connection (e.g. a pad) via which said common calibration signal can be input to said calibration means.
15 . A radar receiver according to claim 14 wherein said feed connection is provided on a common antenna substrate on which said antenna elements are provided,
16 . A radar receiver according to claim 14 wherein said feed connection is provided in one of said first and second processing stages.
17 . A radar receiver according to claim 14 wherein said feed connection (e.g. a pad) is connected to each coupler by a respective calibration path each said calibration path being substantially the same length as each other calibration path.
18 . A radar receiver according to claim 3 wherein said calibration means comprises a substantially planar calibration network.
19 . A radar receiver according to claim 3 wherein each said coupler is arranged for weak coupling to its respective antenna element.
20 . A radar receiver according to claim 3 wherein said calibration means comprises a hierarchy of calibration branches extending from the feed connection to each coupler.
21 .- 47 . (canceled)