As is known in the art, a phased array antenna includes a plurality of antenna elements spaced apart from each other by known distances coupled through a plurality of phase shifter circuits to either or both of a transmitter or receiver. In some cases, the phase shifter circuits are considered to be part of the transmitter and/or receiver. Phased array antenna systems are adapted to produce a beam of radio frequency (RF) energy and direct such beam along a selected direction by controlling the phase of the RF energy passing between the transmitter or receiver and the array of antenna elements. In an electronically scanned phased array, the phase of the phase shifter circuits, and thus the beam direction, may be selected by sending a control signal to each of the phase shifter sections. The control signal is typically a digital signal representative of a desired phase shift, as well as a desired attenuation level and other control data.
Phased array antennas are often used in both defense and commercial electronic systems. For example, Active Electronically Scanned Arrays (AESAs) are in demand for a wide range of defense and commercial electronic systems such as radar surveillance, terrestrial and satellite communications, mobile telephony, navigation, identification, and electronic counter measures. AESAs offer numerous performance benefits over passive scanned arrays as well as mechanically steered apertures. However, the costs that can be associated with deploying AESAs can limit their use. An order of magnitude reduction in array cost could enable widespread AESA insertion into military and commercial systems for radar, communication, and electronic warfare (EW) applications.
There is a desire to lower acquisition and life cycle costs of phased arrays while meeting bandwidth, polarization diversity, and reliability requirements. One way to reduce costs when fabricating RF systems is to utilize printed wiring boards (PWBs)—sometimes referred to as printed circuit boards (PCBs)—which allow use of so-called “mixed-signal circuits.” Mixed-signal circuits typically refer to any circuit having two or more different types of circuits on the same circuit board, for example both analog and digital circuits integrated on a single circuit board.
One type of architecture used for phased array antennas is the so-called “panel” or “tile” architecture. With a panel architecture, the RF circuitry and signals are distributed in a plane that is parallel to a plane defined by the antenna aperture. The tile architecture uses basic building blocks in the form of tiles, wherein each tile can be formed of a multi-layer structure including antenna elements and its associated RF circuitry. To reduce manufacturing and assembly costs, it may be desirable to use PWBs having a single layer of components (or relatively fewer layers) and to interconnect two or more such PWBs to form a panel. Interconnecting (or “mating”) two or more large-area PWBs can be challenging.
One existing approach is to solder connect two or more PWBs and add “bullet” type connects between them. However, this approach may be expensive in terms of cost and time. This is particularly true when a large number of connectors is required. Moreover, the existing approach does not permit “blind mating” of the PWBs. Another existing approach is to use so-called “fuzz buttons,” however fuzz buttons can be difficult to work with resulting in difficult assembly and low yield. Yet another known approach is to use conductive elastomeric pads, but elastomeric pads are generally not suitable high power applications.