fig1 shows an assembled , metallized , ceramic package 10 with the package lid removed . a partially metallized ceramic substrate 12 supports microwave circuit components , not shown , and on its upper surface also supports the input and output lines 13 , 14 , 15 , and 16 . the substrate , shown partially broken away , is preferable a ceramic composite such as a al 2 o 3 / glass composite . metal layers 17 , 18 , 19 , and 20 are deposited on the upper surface and a metallized layer 21 is deposited on the vertical edges of the substrate . as will be shown in greater detail in fig2 , and 4 , substrate 12 maintains a continuous conductive path between the substrate and the main seal ring 22 supported on the substrate . seal ring 22 forms the major vertical substrate of the package and , when attached to the substrate , forms an interior chamber 23 in which the microwave components are supported . seal ring 22 , which is the vertical wall of the package , is also made of ceramic and is metallized on the three surfaces , two of which are shown in fig1 and in greater detail in fig2 - 4 . thus seal ring 22 is metallized along both horizontal surfaces and along the vertical wall . the metallization is patterned to provide electrical isolation for the input and output conductors 13 , 14 , 15 , and 16 . that is , no metal is deposited above or adjacent to input and output leads 13 - 16 to prevent shorting of the leads . similarly , there is no metallization on the underside of seal ring 22 in the areas overlying the input and output lines 13 , 14 , 15 , and 16 . seal ring 22 and substrate 12 are joined by a sealiing glass material deposited over input / output lines 13 , 14 , 15 , and 16 and the non - metallized underside of sealing sing 22 overlying the input - output leads . the sealing glass material is subjected to 500 degrees c . for 20 to 25 minutes to fuse the material and form a bond between the seal ring and the substrate . one commercially available form of the sealing glass material is marketed by the micromaterials company of 87 woodlawn avenue , bristol , r . i . 02809 under its trade designation mmb6111 . seal ring 22 , as pointed out above , is metallized on three surfaces to provide an integral ground between the package lid , not shown , the substrate , and the base . thus , in addition to metallization of the vertical wall , the seal ring is metallized on top surface 24 and on the bottom surface , not shown in fig1 but illustrated in fig3 . fig2 is an exploded view of the package assembly shown in fig1 with the addition of the metallic lid for closing the package . thus , fig2 shows a metal lid 25 , a metal base 26 , substrate 12 , and seal ring 22 . a solder preform 27 is positioned between lid 25 and seal ring 22 and will upon heating and reflow of the solder , fasten the package lid to the metallized top of the seal ring . similarly , a brazing or solder preform 28 is positioned between the underside of substrate 12 and base 26 to secure base 26 to the bottom of metallized ceramic substrate 12 . as may be seen in fig2 seal ring 22 is metallized along the outer vertical surfaces with the exception of the areas 29 , 30 and 31 which are aligned with and overlie input and output leads 13 - 16 on substrate 12 . the underside of seal ring 22 , although not shown in fig2 is also metallized and aligned with the metallized patterns 17 - 20 on the upper surface of substrate 12 to maintain electrical conductivity between seal ring 22 and substrate 12 . the metallized patterns on the upper surface of substrate 12 are also electrically connected with metallization 21 around the outer vertical surfaces of the substrate . similarly , and not shown in fig2 the underside of substrate 12 has a metallization pattern extending to the vertical edge which is aligned with and is of the same shape as solder preform 27 so that heating of the solder preform results in a solder joint being formed between metal base 25 and the metal pattern 34 on the underside of substrate 12 . as can be seen in fig3 seal ring 22 is metallized along three surfaces in the section taken along lines 3 -- 3 of fig2 . the upper and lower horizontal surfaces are covered by metal layers 24 and 34 , and the vertical side wall by layer 32 . as can be seen in fig4 which is a section taken in the area of input / output port 29 , ceramic seal ring 22 is covered by metallization layer 24 on the upper horizontal surface and with a partial verticl layer 32 . vertical layer 32 extends only to the input / output port area over the input and output leads 14 , nor is there metallization along the underside in the area around the input / output lanes in order to prevent short - circuiting of these leads . the solder preforms may typically be a 60 - 40tin lead composition with a melting temperature of 183 degrees c . it will be apparent from the above description that a microwave circuit package has been described which is constituted principally of metallized , ceramic components to provide desired shielding of the microwave components . electrical continuity of the package to provide the desired shielding is achieved by metallizing at least three surfaces of the ceramic components with the metallization patterns being such that they overlie so that conductivity exists between the package lid , the individual package components and the package base to provide a low cost , light weight , and readily manufacturable package .