LPF 2M 1KW+ LDMOS LPF 2M 1KW+ LDMOS is an 1KW+ Filter, developed for use with the latest generation High Power LD Mosfet transistors. These extreme high power semiconductors have very high gain and often amplify up to 600MHz. Because of this high gain and amplification up to 600MHz, a Low Pass Filter can cause serious problems. In a Low Pass Filter, all reflected harmonics and power will be transferred back to the transistor and because the Transistor also amplifies up to 600MHz, it will see a very bad return loss on the harmonics it also produces. This all can give a reduced output, reduced efficiency and a lot of extra heat to dissipate. The design of this filter contains 2 separate sections, one Low Pass Filter section to attenuate the unwanted harmonics and a High Pass Filter with build in 50Ohm Load. This High Pass Filter section is the key in this Filter. It has 2 functions: 1) Let the Mosfet transistor see a good return loss on 2 nd and 3 rd harmonic. 2) Catching most of the reflected harmonics and power from the LPF section. With these 2 sections option we try to get the most out of your LD Mosfet Transistor. For best performance and power handling, we build this LPF on a silver plated Rogers Teflon PCB with silver plated copper wire inductors and Teflon PCB based capacitors. For optimum cooling, the LPF is placed on an 8mm CNC machined aluminium base. Dimension (L x W x H): 152mm x 70mm x 40mm (The picture is a mere example; it does not bind the provided product) Rev 2 04-2016 Page 1 from 5 www.fmbroadcastparts.com
ELECTRICAL SPECIFICATIONS min typ max Power handling 1000 1500* Watt Input impedance 50 Ohm Output impedance 50 Ohm * VSWR 1.25 maximum Input returns loss from 130 450 MHz. Both 2 nd and 3 rd harmonics also have a good input returns loss from the HPF section. (typical values) Signal through filter, measured from 130 450MHz. Attenuation in the pass band is very low and on 2 nd and 3 rd harmonics attenuation is better than 55dB. (typical values) Magnitude Reflection measured with FSH Z2 on R&S FSH3.23 with vector/network analyser option enabled. Magnitude Transmission measured on R&S FSH3.23 with vector/network analyser option enabled. The above data is purely indicative; Fmbroadcastparts is not responsible for changes in values. Rev 2 04-2016 Page 2 from 5 www.fmbroadcastparts.com
Connections INPUT, connect the inner conductor of 50 Ohm Teflon coax like RG142 or similar to this point. Connect the outer conductor of the coax to GND of the PCB, see picture how to connect it the right way. OUTPUT, connect the inner conductor of 50 Ohm Teflon coax like RG142 or similar to this point. Connect the outer conductor of the coax to GND of the PCB, see picture how to connect it the right way. Always use frequency cut coax cables between modules. For Teflon, use 18CM or 36CM measured from begin to end of the outer conductor/shielding of the coax. Rev 2 04-2016 Page 3 from 5 www.fmbroadcastparts.com
Drill plan PCB size 152 x 70mm, drill holes M3, 0x0 is on left top side. Dimensions in mm, drill centre on values calculated from 0x0 Tolerance +/- 0.5mm (if you do not use CNC, use a carpenter pen) Rev 2 04-2016 Page 4 from 5 www.fmbroadcastparts.com
IMPORTANT NOTICE FMBROADCASTPARTS RESERVE THE RIGHT TO MAKE CHANGES TO THE PRODUCT(S) OR INFORMATION CONTAINED HEREIN WITHOUT NOTICE. FMBROADCASTPARTS ASSUMES NO RESPONSIBILITY FOR ANY ERRORS WHICH MAY APPEAR IN THIS DOCUMENT. WARRANTY INFORMATION APPLICABLE TO THE PRODUCT IDENTIFIED HEREIN IS AVAILABLE UPON REQUEST. NOTHING CONTAINED HEREIN SHALL CONSTITUTE A WARRANTY, REPRESENTATION OR GUARANTEE OF ANY KIND. FMBROADCASTPARTS EXPRESSLY DISCLAIMS ALL OTHER WARRANTIES, EXPRESS AND/OR IMPLIED INCLUDING BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY, AND OF FITNESS FOR A PARTICULAR PURPOSE, USE OR APPLICATION. WARNING FMBROADCASTPARTS PRODUCTS ARE NOT INTENDED FOR USE IN LIFE SUPPORT APPLIANCES, DEVICES OR SYSTEMS. USE OF A FMBROADCASTPARTS PRODUCT IN ANY SUCH APPLICATION WITHOUT WRITTEN CONSENT IS PROHIBITED. No part of this document may be copied or reproduced in any form or by any means without the prior written consent of FMbroadcastparts. Rev 2 04-2016 Page 5 from 5 www.fmbroadcastparts.com