Patent Description:
The typical radar assembly includes a printed circuit board (PCB) placed between radar chip packages and radar waveguides to facilitate connections between the devices. The PCB introduces electrical losses that reduce a range of transmission and a range of reception of the radar signals.

<CIT> discloses a package for embedding one or more electronic components, the package comprising a carrier structure, a silicon-based carrier layer, one or more electronic components embedded in one or more cavities formed in the carrier layer, and a cover structure arranged on top of the carrier structure. The cover structure comprises a cover layer and one or more cavities formed in the cover layer. An antenna element and/or a waveguide for connection to an antenna element is formed in and/or on top of the cover layer and coupled to the one or more cavities.

<CIT> discloses a waveguide device module which includes: a waveguide device including an electrically conductive member having an electrically conductive surface, a waveguide member extending alongside the electrically conductive surface and having an electrically-conductive waveguide face, and a first artificial magnetic conductor extending on both sides of the waveguide member; a coupler including a first face having a groove, a second face opposite to the first face, and a throughhole extending from the first face through to the second face.

Further prior art is mentioned in <CIT> which discloses formations for circuit waveguide interfaces during a wafer-scale die packaging (WSDP) process.

The invention is defined by the independent claims <NUM> and <NUM>. Advantageous embodiments of the invention are described in the sub claims.

<FIG> is an illustration of a transceiver <NUM> configured to transmit and receive electromagnetic signals. In an example, the transceiver <NUM> transmits and receives the electromagnetic signals in a <NUM> to <NUM> frequency band, such as those used in automotive radar systems. The transceiver <NUM> includes a chip package <NUM> including a die <NUM> including at least one transmitter <NUM> and at least one receiver <NUM>. The at least one transmitter <NUM> and at least one receiver <NUM> transmit and receive the electromagnetic signals (i.e., the radar signals) through antennas <NUM> (see <FIG>) in communication with the chip package <NUM>. In the example illustrated in <FIG>, the chip package <NUM> is a monolithic microwave integrated circuit (MMIC) having a ball grid array (BGA) of interconnects (not shown) on an exterior surface <NUM>. In this example, the chip package <NUM> supports three transmitters <NUM> and four receivers <NUM>. It will be appreciated that the chip package <NUM> may support any number of transmitters <NUM> and receivers <NUM> within the dimensional limits of the chip package <NUM>.

Air waveguides <NUM> are placed between the chip package <NUM> and the antennas <NUM> to transport the radar signals being transmitted and received. The air waveguide <NUM> is a hollow metal structure that is capable of directing electromagnetic power from one area to another area. The transceiver <NUM> is an improvement over other transceivers, because the transceiver <NUM> eliminates an intermediate printed circuit board (PCB) that may be placed between chip packages and waveguides to facilitate connections between the devices. The PCB introduces electrical losses that reduce a range of transmission and a range of reception of the radar signals. In addition, inclusion of the PCB results in added material and manufacturing costs.

Referring back to <FIG>, the transceiver <NUM> includes a first plurality of electrical channels <NUM> (i.e., signal transmission lines) configured to transfer first electromagnetic signals to a first plurality of air waveguides 22A. In the example illustrated in <FIG>, the first electromagnetic signals are the transmitted radar signals, and the air waveguides <NUM> are WR10 air waveguides <NUM>. WR10 designates that the waveguide is rectangular, with the dimensions of <NUM> by <NUM>. Slight variations of these dimensions does not significantly deteriorate the performance of the waveguide, and the rectangular shape need not be a "perfect" rectangle. The dimensions of the air waveguide <NUM> establish a limit on a frequency of the electromagnetic signal that may be passed through the air waveguide <NUM>. The air waveguides <NUM> may be formed with a tortuous path (i.e., bends) to direct the radar signals to and from the antennas <NUM> that may be arranged in an antenna array.

Each of the first plurality of electrical channels <NUM> extend from outputs of at least one transmitter <NUM> along the exterior surface <NUM> of the chip package <NUM>. That is, the first plurality of electrical channels <NUM> run along an outside of the chip package <NUM> and are exposed to the environment (e.g., air). In some configurations, this exposure results in about half of the guiding power propagating into the exterior surface <NUM>, and about half of the guiding power propagating in the air. Because air has nearly no loss, this configuration ensures low transmission line losses.

The first plurality of electrical channels <NUM> terminate at first transitions <NUM> disposed on the exterior surface <NUM>. The first transitions <NUM> are a link between the transmission lines and the air waveguides <NUM>, and will be described in more detail below. Each of the first plurality of air waveguides 22A are attached to the exterior surface <NUM> of the chip package <NUM> and overlay one of the first transitions <NUM>. In an example, the first plurality of air waveguides 22A are integrated into a waveguide antenna assembly that is attached to the exterior surface <NUM> of the chip package <NUM>. In this example, ends of the first plurality of air waveguides 22A are arranged within a surface of the waveguide antenna assembly to overlay the first transitions <NUM>. The ends of the first plurality of air waveguides 22A that overlay the first transitions <NUM> may be open, or may be partially closed (e.g., slotted), as will be described in more detail below.

The transceiver <NUM> also includes a second plurality of electrical channels <NUM> configured to transfer second electromagnetic signals from a second plurality of air waveguides 22B. In the example illustrated in <FIG>, the second electromagnetic signals are the received radar signals (i.e. the radar signals reflected from a target), and the air waveguides <NUM> are the WR10 air waveguides <NUM>. Each of the second plurality of electrical channels <NUM> extend from an input of at least one receiver <NUM> along the exterior surface <NUM> of the chip package <NUM>. The second plurality of electrical channels <NUM> terminate at second transitions <NUM> disposed on the exterior surface <NUM>. Each of the second plurality of air waveguides 22B are attached to the exterior surface <NUM> and overlay one of the second transitions <NUM>. In an example, the second plurality of air waveguides 22B are integrated into the waveguide antenna assembly that is attached to the exterior surface <NUM> of the chip package <NUM>. In this example, ends of the second plurality of air waveguides 22B are arranged within the surface of the waveguide antenna assembly to overlay the second transitions <NUM>. The ends of the second plurality of air waveguides 22B that overlay the second transitions <NUM> may be open, or may be partially closed (e.g., slotted), as will be described in more detail below.

<FIG> illustrate examples of the first plurality of electrical channels <NUM> and/or the second plurality of electrical channels <NUM> that include differential pairs of microstrips <NUM>. The differential pair of microstrips <NUM> are formed of two, parallel metallic strips having a constant spacing along their length. One of the metallic strips is connected to a positive terminal of the respective transceiver <NUM> channel, and the other metallic strip is connected to a negative terminal of the respective transceiver <NUM> channel. The microstrips <NUM> are formed of metals, such as copper, aluminum, silver, gold, and alloys thereof, and may be formed on the exterior surface <NUM> by any of the known methods of deposition, such as physical vapor deposition. The microstrips <NUM> may be separated using techniques such as photolithography and/or micromachining. In the examples illustrates in <FIG>, the differential pairs of microstrips <NUM> terminate in a region of the exterior surface <NUM> of the chip package <NUM> that is surrounded by a solder ball fence <NUM>. One side of the solder ball fence <NUM> defines a gap (i.e., a "mouse hole") through which the differential pairs of microstrips <NUM> pass. The solder ball fence <NUM> provides electromagnetic shielding for the air waveguides <NUM>.

<FIG> illustrate examples of the first plurality of electrical channels <NUM> and the second plurality of electrical channels <NUM> that include co-planar waveguides <NUM>. The co-planar waveguides <NUM> are formed of three, parallel, metallic strips having a constant spacing along their length. A center metallic strip is connected with a positive terminal of the respective transceiver <NUM> channel, and the other two metallic strips are attached to a negative terminal of the respective transceiver <NUM> channel. The co-planar waveguides <NUM> are formed of metals, such as copper, aluminum, silver, gold, and alloys thereof, and may be applied to the exterior surface <NUM> by any of the known methods of deposition, such as physical vapor deposition. The co-planar waveguides <NUM> may be separated using techniques such as photolithography and/or micromachining. In the examples illustrates in <FIG>, the co-planar waveguides <NUM> also terminate in a region of the exterior surface <NUM> of the chip package <NUM> that is surrounded by the solder ball fence <NUM>. One side of the solder ball fence <NUM> defines the gap through which the co-planar waveguides <NUM> pass. The co-planar waveguides <NUM> are arranged so that a <NUM>-degree turn is made before passing through the gap, which assists in the conversion of the electromagnetic signals from the co-planar waveguides <NUM> to the air waveguides <NUM>. That is, the <NUM>-degree bend aligns a polarization of the co-planar waveguide <NUM> with the air waveguide <NUM> for maximum transition efficiency.

In an example, the first plurality of electrical channels <NUM> and the second plurality of electrical channels <NUM> are of the same design (i.e., all differential pairs of microstrips <NUM> or all co-planar waveguides <NUM>). In another example, the first plurality of electrical channels <NUM> and the second plurality of electrical channels <NUM> are of different designs. In an example, the first plurality of electrical channels <NUM> and the second plurality of electrical channels <NUM> terminate at first transitions <NUM> and second transitions <NUM> that are of the same design. In another example, the first plurality of electrical channels <NUM> and the second plurality of electrical channels <NUM> terminate at first transitions <NUM> and second transitions <NUM> that are of a different design. The following descriptions of the first plurality of electrical channels <NUM>, the first transitions <NUM>, and the first plurality of air waveguides 22A will also apply to the second plurality of electrical channels <NUM>, the second transitions <NUM>, and the second plurality of air waveguides 22B.

<FIG> illustrates the differential pairs of microstrips <NUM> that terminate at the first transitions <NUM> which include a pair of opposed solder ball transitions <NUM>. The pair of opposed solder ball transitions <NUM> may be formed of any solder alloy compatible with the chip package <NUM>, such as alloys of silver and/or alloys of gold. In this example, the first plurality of air waveguides 22A include slotted air waveguides 22C where the slot is positioned between the pair of opposed solder ball transitions <NUM>. In this example, the end of the slotted air waveguide 22C that overlays the pair of opposed solder ball transitions <NUM> is closed except for the slot. The pair of opposed solder ball transitions <NUM> are in electrical contact with the slotted end of the slotted air waveguide 22C. The slot is an opening in the end of the slotted air waveguide 22C and disrupts the electric and magnetic fields established between the solder balls. This disruption in the fields enables the radar signal to propagate along a particular axis through the slotted air waveguides 22C.

<FIG> illustrates the differential pairs of microstrips <NUM> that terminate at the first transitions <NUM> which include loop transitions 38A. In this example, the loop transition 38A is continuous rectangular metallic loop that connects the differential pairs of microstrips <NUM>. The loop transition 38A may be formed of metals, such as copper, aluminum, silver, gold, and alloys thereof. In this example, the end of the air waveguide 22A that overlays the loop transition 38A is open. The loop transition 38A has a perimeter equal to about one wavelength of the radar signal. The magnetic field surrounding the loop transition 38A, created by the electrical current flow through the loop, generates the electromagnetic signal that is transported through the air waveguide 22A.

<FIG> illustrates the differential pairs of microstrips <NUM> that terminate at the first transitions <NUM> which include bowtie transitions <NUM>. The bowtie transitions <NUM> may be formed of metals, such as copper, aluminum, silver, gold, and alloys thereof. In this example, the bowtie transitions <NUM> are triangular metal pads that are in contact with the differential pairs of microstrips <NUM>. In this example, the end of the air waveguide 22A that overlays the bowtie transition <NUM> is open. An angle between the opposing triangular metal pads of the bowtie transitions <NUM> specifies the frequency bandwidth of this first transition <NUM>, as opposed to a perimeter dimension. The bowtie transition <NUM> is capable of operating in a wider range of frequencies, compared to the loop transition 38A.

<FIG> illustrates the co-planar waveguides <NUM> that terminate at the first transitions <NUM> which include monopole transitions <NUM>. The monopole transitions <NUM> are formed by extensions of the co-planar waveguides <NUM> into the region overlaid by the end of the air waveguide <NUM>. The monopole transitions <NUM> may be formed of metals, such as copper, aluminum, silver, gold, and alloys thereof. In this example, the end of the air waveguide 22A that overlays the monopole transitions <NUM> is open. In this example, the length of the positive strip (i.e. the monopole) that extends into the region overlaid by the air waveguide <NUM> is equal to about one quarter of the wavelength of the radar signal. The two negative strips on either side of the monopole form a ground plane. The magnetic field surrounding the monopole transitions <NUM>, created by a voltage potential between the monopole and the ground plane, generates the electromagnetic signal that is transported through the air waveguide 22A.

<FIG> illustrates the co-planar waveguides <NUM> that terminate at the first transitions <NUM> which include loop transitions 38B. In this example, the loop transition 38B includes a continuous rectangular metallic loop that connects the two negative strips of the co-planar waveguide <NUM>, and is bifurcated by the positive strip of the co-planar waveguides <NUM>, creating two loops with equal perimeters. The loop transition 38B may be formed of metals, such as copper, aluminum, silver, gold, and alloys thereof. In this example, the end of the air waveguide 22A that overlays the loop transition 38B is open. Each of the two loops in the loop transition 38B has a perimeter of about one half of a wavelength of the radar signal. The magnetic field surrounding the loop transition 38B, created by the electrical current flow through the two loops, generates the electromagnetic signal that is transported through the air waveguide 22A.

<FIG> illustrates the co-planar waveguides <NUM> that terminate at the first transitions <NUM> which include patch transitions <NUM>. The patch transitions <NUM> may be formed of metals, such as copper, aluminum, silver, gold, and alloys thereof. In this example, the end of the air waveguide 22A that overlays the patch transitions <NUM> is open. In this example, the patch transitions <NUM> are rectangular metal pads that are in contact with the positive strip of the co-planar waveguides <NUM>. The two negative strips form the ground plane. A length of the patch transitions <NUM> is about one half of a wave length, and the patch transitions <NUM> radiate the electromagnetic energy into the air waveguide <NUM> similar to an antenna <NUM>. The magnetic field surrounding the patch transitions <NUM>, created by the voltage potential between the patch and the ground plane, generates the electromagnetic signal that is transported through the air waveguide 22A.

Claim 1:
A transceiver (<NUM>), comprising:
a plurality of electrical channels (<NUM>) configured to transfer electromagnetic signals to a plurality of air waveguides (22A), the plurality of electrical channels each comprising a differential pair of microstrips (<NUM>) having first and second microstrips in the form of parallel metallic strips having a constant spacing along their length,
the first microstrip connected to a positive terminal of a respective transceiver channel and the second microstrip connected to a negative terminal of the respective transceiver channel, each electrical channel in the plurality of electrical channels comprising an electrical channel that extends from an output of at least one transmitter (<NUM>) and / or an input of at least one receiver (<NUM>) along an exterior surface (<NUM>) of a chip package (<NUM>) and terminates at a transition (<NUM>, <NUM>) that provides a link between the respective electrical channel and an air waveguide (<NUM>) that overlays the transition, the transition comprising a region of an exterior surface (<NUM>) of the chip package (<NUM>), the chip package configured to support the at least one transmitter (<NUM>) and / or the at least one receiver (<NUM>), the region being overlaid by an end of the air waveguide and surrounded by a solder ball fence configured to provide electromagnetic shielding for the air waveguide, one side of the solder ball fence defining a gap through which the differential pair of microstrips pass, the transition including an arrangement selected from the group consisting of:
a pair of opposed solder ball transitions (<NUM>) that are in electrical contact with the end of the air waveguide that includes a slot, the slot being positioned between the pair of opposed solder ball transitions; and
multiple bowtie transitions comprising opposing triangular metal pads that are in contact with the differential pairs of microstrips, the end of the air waveguide that overlays the region being open.