An electronic device, comprising: a housing; a baseband processor; a plurality of phased antenna arrays having first and second phased antenna arrays, the first phased antenna array having a first metal ground layer, a first array of antenna elements, a first dielectric layer interposed between the first metal ground layer and the first array of antenna elements, and the second phased antenna array having a second metal ground layer, a second array of antenna elements, and a second dielectric layer interposed between the second metal ground layer and the second array of antenna elements; a plurality of transceiver circuits (46B, 90) each of which is associated with a respective one of the phased antenna arrays and each of which includes an upconverter and a downconverter; and a plurality of intermediate frequency signal paths each of which is coupled between the baseband processor and a respective one of the transceiver circuits, wherein each of the upconverters in the plurality of transceiver circuits is configured to receive intermediate frequency signals from the baseband processor over a respective one of the plurality of intermediate frequency signal paths and is configured to upconvert the received intermediate frequency signals to radio-frequency signals that are provided to a respective one of the phased antenna arrays, and each of the downconverters in the plurality of transceiver circuits is configured to receive radio-frequency antenna signals from the respective one of the phased antenna arrays and is configured to downconvert the received radio-frequency antenna signals to intermediate frequency signals that are conveyed to the baseband processor over the respective one of the intermediate frequency signal paths, and wherein antenna circuitry including the corresponding upconverter and the corresponding downconverter in one of the plurality of transceiver circuits is mounted within a cavity between the first and second dielectric layers, further comprising additional dielectric layers that attach the first and second dielectric layers forming the cavity. a housing; a baseband processor; a plurality of phased antenna arrays having first and second phased antenna arrays, the first phased antenna array having a first metal ground layer, a first array of antenna elements, a first dielectric layer interposed between the first metal ground layer and the first array of antenna elements, and the second phased antenna array having a second metal ground layer, a second array of antenna elements, and a second dielectric layer interposed between the second metal ground layer and the second array of antenna elements; a plurality of transceiver circuits (46B, 90) each of which is associated with a respective one of the phased antenna arrays and each of which includes an upconverter and a downconverter; and a plurality of intermediate frequency signal paths each of which is coupled between the baseband processor and a respective one of the transceiver circuits, wherein each of the upconverters in the plurality of transceiver circuits is configured to receive intermediate frequency signals from the baseband processor over a respective one of the plurality of intermediate frequency signal paths and is configured to upconvert the received intermediate frequency signals to radio-frequency signals that are provided to a respective one of the phased antenna arrays, and each of the downconverters in the plurality of transceiver circuits is configured to receive radio-frequency antenna signals from the respective one of the phased antenna arrays and is configured to downconvert the received radio-frequency antenna signals to intermediate frequency signals that are conveyed to the baseband processor over the respective one of the intermediate frequency signal paths, and wherein antenna circuitry including the corresponding upconverter and the corresponding downconverter in one of the plurality of transceiver circuits is mounted within a cavity between the first and second dielectric layers, further comprising additional dielectric layers that attach the first and second dielectric layers forming the cavity.