一、Characteristics

       The main function of the LTCC diplexer (also known as the low-temperature co-fired ceramic laminated diplexer) is to isolate the received signal and the transmission to ensure that the receive and transmission can work properly at the same time, avoiding the transmission of the local signal to the receiver. The diplexer is actually composed of two bandpass filters, which use filtering to distinguish the frequency range of the input or output signal, so as to ensure that two different signal sources do not interfere with each other and have bandwidth control capabilities. Another function of the LTCC diplexer is to allow two different signal sources to share the same transmission medium in order to complete the communication task in a limited space, improving the efficiency of communication.

       The production technology of LTCC duplexer is to use low temperature sintered ceramic powder process and implant a number of passive elements buried in the multi-layer ceramic substrate, and then mount IC and active electrical appliances on its surface, so as to make active/passive integrated function module. In addition to a variety of filter architectures, miniaturized integration advantages and higher flexibility of the design features, LTCC diplexers also have input/output 50Ω impedance matching (75Ω needs special description), easy to cascade use; The performance is stable and reliable in the whole temperature range, and meets the requirements of military working environment (-55℃ ~ +85℃). It has the advantages of high inhibition, high isolation, wide frequency band, low insertion loss, good thermal stability, low temperature coefficient, surface mounting, small size, light weight, convenient welding, and cheap price.

LTCC duplexer

二、Electrical Characteristics

LTCC diplexer  model and parameter table
Part No	Frequency (MHz)	Insertion loss （dB）	V.S.W.R	Size（mm）	SPEC
LD22L1002H1125-D94	5 -- 1002 / 1125 -- 1675	≤ 1.8 / ≤ 7.1	≤ 4.1 / ≤ 4.1	2.5 * 2.0 * 1.5
LD22L1653H4625-D50	617 -- 2690 / 3300 -- 5925	≤0.4/≤0.65 /≤1.4/≤0.6	≥14dB/≥12dB/≥ 9.6dB/≥ 9.6 dB	2.5 * 2.0 * 0.65
LD21L2690H3300-D88	617 -- 2690 / 3300 -- 5925	≤0.35/≤1.67 /≤1.3/≤0.5	≤ 1.5 / ≤ 0.9 / ≤ 1.67 / ≤ 1.5	2.0 * 1.25 * 0.6
LD18L27H33-D81	698 -- 2690 / 3400 -- 5850	≤ 0.8 / ≤ 0.89 / ≤ 0.54	≥ 9.54 dB / ≥ 9.54 dB	1.6 * 0.8 * 0.6
LD21L09H17-D80	698 -- 960 / 1710 -- 2700	≤ 0.4 / ≤ 0.5  /≤ 0.5	≥ 10 dB / ≥ 10 dB	2.0 * 1.25 * 0.9
LD21L09H17-D80/M	698 -- 960 / 1710 -- 2700	≤ 0.4 / ≤ 0.5  /≤ 0.5	≥ 10 dB / ≥ 10 dB	2.0 * 1.25 * 0.9
LD21L09H17-D72	698～960/1710～2700	≤ 0.8 / ≤ 0.7	≥ 9.6 dB / ≥ 9.6 dB	1.6 * 0.8 * 0.6
LD21L09H17-D72/M	698～960/1710～2700	≤ 0.8 / ≤ 0.7	≥ 9.6 dB / ≥ 9.6 dB	1.6 * 0.8 * 0.6
LD32L1530H1710-D95	880 -- 1530 / 1710 -- 2700	≤0.8/≤2.4/≤2.5/≤1.8	≥ 12 dB / ≥ 12 dB	3.2 * 2.5 * 1.2
LBF43ML1220H2215-M29	950--1450 / 200--750 / 1650--2150	≤ 3.5 ≤ 2.5 / ≤ 2.5	≤ 2.0	4.5 * 3.2 * 2.0
LBF43ML1200H920-M09/A	970 --1470 / 330 --830 / 1730 --2230	≤ 3.0 / ≤ 3.0 / ≤ 3.0	≤ 2.0	4.5 * 3.2 * 2.0
LBF43ML1220H2215-M30	970 --1470 / 330 --830 / 1730 --2230	≤ 3.0 / ≤ 3.0 / ≤ 3.0	≤ 2.0	4.5 * 3.2 * 2.0
LD22L2814H5538-D51	1427 --4200 / 5150 --5925	≤ 0.8 / ≤ 1.15	≥ 9.5 dB / ≥ 7.7 dB	2.5 * 2.0 * 0.7
LD18L1583LAN-D85	1559 --1607  / 2400 --5950	≤ 0.85 / ≤ 0.9 / ≤ 0.65	≥ 10 dB / ≥ 10 dB	1.6 * 0.8 * 0.6
LD18D1584LAN-D61	1560 --1607 / 2400 -- 2500	≤ 0.45 / ≤ 0.5	≤ 1.6 / ≤ 1.5	1.6 * 0.8 * 0.6
LD18GPS2450-D27	1560 --1607 / 2400 -- 2500	≤ 0.6 / ≤ 0.8	≤ 1.6 / ≤ 1.5	1.6 * 0.8 * 0.6
LD18L1583LAN-D62	1570 -- 1610 / 2400 --6000	≤0.6 / ≤0.7 / ≤0.7  / ≤0.6	≤ 2.0 / ≤ 2.0	1.6 * 0.8 * 0.6
LD18L1583LAN-D62/M	1570 -- 1610 / 2400 --6000	≤0.75 / ≤0.8 / ≤0.6	≤ 2.0 / ≤ 2.0	1.6 * 0.8 * 0.6
LD18D2450LAN-D33/T	2400～2500/ 5150～5850	≤ 0.75 / ≤ 1.7	≥ 2.0 / ≥ 2.0	1.6 * 0.8 * 0.6
LD21D2450LAN-D31/H	2400～2500/ 5150～5850	≤ 0.45 / ≤ 0.5	≥ 10 dB / ≥ 10 dB	2.0 * 1.25 * 0.6
LD21D2450LAN-D31/MH	2400～2500/ 5150～5850	≤ 0.4 / ≤ 0.45	≥ 10 dB / ≥ 10 dB	2.0 * 1.25 * 0.6
LD18D2450LAN-D41	2400～2500/ 5150～5850	≤ 0.5 / ≤ 0.7	≥15 dB / ≥15 dB	1.6 * 0.8 * 0.6
LD18D2450LAN-D41/M	2400～2500/ 5150～5850	≤ 0.5 / ≤ 0.7	≥15 dB / ≥15 dB	1.6 * 0.8 * 0.6
LD15D2450LAN-D93	2400 --2500 / 5150 --5850	≤ 0.5  / ≤ 0.8	≤ 2.0 / ≤ 2.0	1.0 * 0.5 * 0.4
LD18D2450LAN-D49/G	2400～2500/ 5150～5850	≤ 0.5 / ≤ 0.7	≥15 dB / ≥15 dB	1.6 * 0.8 * 0.6
LD18D2450LAN-D25	2400～2500 / 4900～5950	≤ 0.6 / ≤ 0.85	≤ 1.8	1.6 * 0.8 * 0.6
LD18D2450LAN-D25/F	2400～2500 / 4900～5950	≤ 0.6 / ≤ 0.85	≤ 1.8	1.6 * 0.8 * 0.6
LD18D2450LAN-D26	2400～2500 / 4900～5950	≤ 0.6 / ≤ 0.85	≤ 1.8	1.6 * 0.8 * 0.6
LD18D2450LAN-D26/F	2400～2500 / 4900～5950	≤ 0.6 / ≤ 0.85	≤ 1.8	1.6 * 0.8 * 0.6
LD18D2450LAN-D34	2400～2500 / 4900～5950	≤ 0.5 / ≤ 0.6	≤ 2.0 / ≤ 2.0	1.6 * 0.8 * 0.6
LD18D2450LAN-D34/M	2400～2500 / 4900～5950	≤ 0.5 / ≤ 0.6	≤ 2.0 / ≤ 2.0	1.6 * 0.8 * 0.6
LD18D2450LAN-D40/M	2400～2500 / 4900～5950	≤ 0.9 / ≤ 1.1	≥ 13 dB / ≥ 13 dB	1.6 * 0.8 * 0.6
LD18D2450LAN-D43	2400～2500 / 4900～5950	≤ 0.6 / ≤ 0.8	≤ 1.8 / ≤ 1.8	1.6 * 0.8 * 0.6
LD18D2450LAN-D91	2400～2500 / 4900～5950	≤ 0.75 / ≤ 1.5 / ≤ 1.2	≥ 13 dB / ≥ 13 dB	1.6 * 0.8 * 0.7
LD18D2450LAN-D30	2400～2500 / 4900～5950	≤ 0.6 / ≤ 0.8	≤ 1.8 / ≤ 1.8	1.6 * 0.8 * 0.6
LD18D2450LAN-D30/M	2400～2500 / 4900～5950	≤ 0.6 / ≤ 0.8	≤ 1.8 / ≤ 1.8	1.6 * 0.8 * 0.6
LD18D2450LAN-D86	2400～2500/4900～6000	≤ 0.85 / ≤ 0.85	≥ 15 dB / ≥15 dB	1.6 * 0.8 * 0.6
‍LD18D2450LAN-D73	2400～2500/5150～7125	≤ 0.75 / ≤ 1.25	≥ 13 dB / ≥ 11 dB	1.6 * 0.8 * 0.6
‍LD18D2450LAN-D87/T	2400～2500/5150～7125	≤ 0.7 / ≤ 1.2 /≤ 1.1	≤ 1.5 / ≤ 1.58	1.6 * 0.8 * 0.6
Note: Due to many product models, only some representative models are listed in the table

三、Application & attention

       LTCC duplexers are widely used in radio, broadcast, radar, navigation, electronic reactance, router, mobile phone signal amplifier and other RF circuits. In radar or satellite communications, duplexers can achieve simultaneous transmission and reception of signals, improving the efficiency of communication. It is usually used to distinguish between the frequency of sending and receiving signals, and has the ability to control bandwidth. In use, but pay attention to the grounding end is well grounded, otherwise it will affect out-of-band suppression and flatness indicators, welding temperature is best to use the recommended temperature, not too high, the time can not be too long. If reflow welding is used, the recommended temperature is recommended, and wave soldering is not recommended. Products should be stored in the ambient temperature of -10℃~40℃, relative humidity is not more than 80%, the surrounding environment is not acidic, alkaline and other harmful gases in the warehouse. It is recommended to wipe with alcohol when cleaning.

     In addition to customized LTCC duplexers, the company also accepts customized LTCC filter, LTCC low-pass filter, LTCC high-pass filter, LTCC power divider, LTCC Balun and other products. Because the indicators of microwave components are related to each other and sound to each other, the user needs to clearly state the indicator requirements before customization. Once the product is made, it cannot be changed. If there are indicators that exceed the physical limit of the material itself, the best indicators can be achieved through negotiation between the two parties.