Abstract: Electronic VHF/UHF power conversion circuitry is manufactured using the benefits of low temperature co-fired ceramic substrates to provide interconnection between the discrete components of the power conversion circuit, and integrate various non-semiconductor devices into the body of the low temperature co-fired ceramic structure, such as resistors, capacitors, inductors and transformers. Use of a low temperature co-fired ceramic structure as a substrate on and within which VHF/UHF power conversion circuitry is formed allows selection of various conductive and resistive inks to precisely form interconnection circuitry and selected non-semiconductor components which improves the stability and reduces the cost of VHF/UHF power conversion circuits.

Abstract: A ferromagnetic material (18,20) in ink or tape form is sinterable using a same firing profile as and has approximately the same thermal shrinkage characteristics as low-temperature-cofired-ceramic (LTCC) tape, and is chemically non-reactive therewith. The ferromagnetic material (18,20) is applied to the surfaces of LTCC tape sheets (12,14,16) to form desired elements such as cores for inductors (22) and transformers and magnetic shields. Ferromagnetic vertical interconnects (vias) (54) can be formed by punching holes (56) through tape sheets (46) and filling them with ferromagnetic ink. The tape sheets (12,14,16) and ferromagnetic elements (18,20) are laminated together and cofired to form an integral structure (10). Ferromagnetic and non-magnetic components (114) can be fabricated separately and inserted into cavities (104a,-106a,108a) in tape sheets (104,106,108) prior to cofiring.

Abstract: An electrically conductive stripline (16) is formed on a thermally fusible sheet (10), with a portion (16a) of the stripline (16) extending adjacent to an edge (10a) of the sheet (10). A cavity (18) is formed in another thermally fusible sheet (12) having an end (18) at an edge (12a) thereof. The sheets (10,12) are laminated together with their edges (10a,12a) aligned, and the cavity (18) aligned with and facing the edge portion (16a) of the stripline (16). A retaining pin (20) may be temporarily inserted into the cavity (18) to prevent collapse thereof during the lamination step. The laminated sheets (10,12) are heated to thermally fuse them together. An electrically conductive pin (28) is partially inserted into the cavity (18) and ohmically bonded to the stripline (18) to provide an external connection.

Abstract: A ferromagnetic material (18,20) in ink or tape form is sinterable using a same firing profile as and has approximately the same thermal shrinkage characteristics as low-temperature-cofired-ceramic (LTCC) tape, and is chemically non-reactive therewith. The ferromagnetic material (18,20) is applied to the surfaces of LTCC tape sheets (12,14,16) to form desired elements such as cores for inductors (22) and transformers and magnetic shields. Ferromagnetic vertical interconnects (vias) (54) can be formed by punching holes (56) through tape sheets (46) and filling them with ferromagnetic ink. The tape sheets (12,14,16) and ferromagnetic elements (18,20) are laminated together and cofired to form an integral structure (10). Ferromagnetic and non-magnetic components (114) can be fabricated separately and inserted into cavities (104a, 106a,108a) in tape sheets (104,106,108) prior to cofiring.

Abstract: An electrically conductive stripline (16) is formed on a thermally fusible sheet (10), with a portion (16a) of the stripline (16) extending adjacent to an edge (10a) of the sheet (10). A cavity (18) is formed in another thermally fusible sheet (12) having an end (18a) at an edge (12a) thereof. The sheets (10,12) are laminated together with their edges (10a,12a) aligned, and the cavity (18) aligned with and facing the edge portion (16a) of the stripline (16). A retaining pin (20) may be temporarily inserted into the cavity (18) to prevent collapse thereof during the lamination step. The laminated sheets (10,12) are heated to thermally fuse them together. An electrically conductive pin (28) is partially inserted into the cavity (18) and ohmically bonded to the stripline (18) to provide an external connection.

Abstract: An airline transmission structure in a low temperature co-fired ceramic ("LTCC"). A cavity is made within the LTCC structure. Ground planes surround the cavity. Electronic processing circuitry, such as an airline filter, is suspended within the cavity. Transmission lines are provided to connect the electronic circuitry to the electronic signals (typically microwave) which require processing. Full integration of the airline filter with other electronic circuitry in a single LTCC package is also shown.

Abstract: A technique is disclosed for trimming resistors and other passive circuit components buried in hybrid multilayer circuit structures. For example, resistors (13) are formed between two dielectric layers (11, 19) of a hybrid multilayer circuit structure (10). The multilayer circuit structure with the buried resistors is appropriately processed to provide a fired multilayer circuit structure. Trimming of the buried resistors is accomplished with a laser beam that cuts through dielectric material of the fired circuit structure to selectively remove part of the resistive material of the buried resistors. The values of the buried resistors may be tested with conductive elements (15, 17) that are conductively coupled to the buried resistors. The disclosed technique also contemplates the trimming of other buried passive circuit components such as capacitors, and further contemplates the use of other trimming methods such as abrasive, air jet, or water jet trimming.