Towards a 3D printed terahertz circuit technology.

Lead Research Organisation: University of Birmingham
Department Name: Electronic, Electrical and Computer Eng


Three-dimensional (3D) printing, also known as additive manufacturing, is now common place in many industries and is used widely. Some types of 3D printers are available for home use at modest cost. However, detailed work, together with demonstrator devices, is still in the very early stages in relation to the manufacture of microwave and terahertz circuits. These requires a level of precision and materials very different from the consumer products.

This proposal is to evaluate and improve the performance of 3D printing for microwave and terahertz passive and diode circuits through measurement, design and demonstration. These high frequencies, from 10 GHz to 1000 GHz, are used for free space communications, security sensing and remote monitoring of the Earth's atmosphere. The focus will be on evaluation of 3D printed circuits at frequencies above about 50 GHz, the small feature sizes required for these frequencies allows only the best printing process to compete; enabling the project to evaluate the most advanced 3D printing approaches. This exciting project will be the most comprehensive academic study worldwide to date.

A strong, experienced, national team, at the University of Birmingham and the STFC Rutherford Appleton Laboratory (RAL) will conduct the research in collaboration with several UK and international industry partners. The Communications and Sensing research group at Birmingham University have already demonstrated significant research in this area, with 3D printed devices published covering the frequency range 0.5 GHz to 100 GHz. The importance of this work has been recognised externally through prizes, invited international presentations and refereed academic publications. Birmingham's partners, the Millimetre Wave Technology Group in the RAL Space department, bring extensive expertise in precision manufacturing of conventional devices for these high frequencies, and knowledge of the demanding space and other requirements that the new 3D circuits must fulfil. RAL staff will conduct post processing of the 3D printed circuits and perform accelerated lifetime measurements under conditions of elevated temperature and humidity.

3D printed microwave and terahertz circuits will have an important beneficial economic impact on UK industry, not only because complex circuits become possible at low cost, but because new design approaches emerge because of the unique manufacturing. The applicants will both work on their own ideas, and closely with industrial partners, during the project. There are a number of hurdles to overcome before the technology becomes mainstream: this proposal tackles these challenges.

The advantages of 3D printing include the availability to rapidly generate novel circuits with complex shapes and multiple functions using low material volumes in a lightweight form. This enables reliable, low cost, superior performance circuits with less waste and reductions in lead time. Considerations to be addressed include the metal coating of polymer circuits which adds an extra step in the production, as well as potentially lower thermal stability and power handling of such circuits. If the polymer is used as a microwave dielectric, power loss may be a problem. For metal 3D printed circuits, power handling and thermal stability is good, but surface roughness may reduce device performance. These problems and others are addressed in the proposal with a methodical investigation based on the measurement of resonant waveguide cavities, the microwave equivalent of a tuning fork. Changes to the frequency and decay time indicate the quality of manufacture.

The project will inform industry and academia through a widely distributed technology development roadmap and external collaborative projects, as well as the provision of advice and guidance. Our finding will also be communicated to national and international colleagues through academic publications, and presentations at relevant conferences.

Planned Impact

This project will have a strong impact on a range of industrial sectors. Microwave devices are ubiquitous in all industries and whatever sector is chosen examples of the importance of them can be given. Birmingham have extensive capabilities in terahertz communications (via joint EPSRC work with RAL) and automotive radar for autonomous vehicles and RAL have world class expertise in the space industry.

This project is about moving 3D printed technology, as applied to microwave passive components, efficiently into industrial use. To do this the basic manufacturing is evaluated and improved and device design principles developed. Demonstrators are produced with specific industrial collaborators. The project will have TRL levels 1-4, with collaboration with industry moving to TRL 5 with specific successful designs.

The demonstrators with specific industrial collaborators are an important part of the project; here industry will provide specifications. The demonstrators include:

1. Complex beam forming networks for airborne and satellite environment with integrated feedhorns, polarisers and filters
2. A 220 GHz frequency tripler.
3. A satellite communications orthomode transducer
4. 5G communications from end demonstrator
5. D band multiplexer with polarisation control.
6. Integration of horns, polarisers, OMT and filters with twits and bends in waveguide
7. 300 GHz screen printed filters

With a range of new, novel designs produced in the course of the work, the expectation is that some will be patentable and more will be capable of commercial exploitation.

As well as collaboration with industry on each of the above demonstrators, there is also the Birmingham industrial steering group which will oversees the project. This has members from TeraTech Components, Elite Antennas, BAE Systems, Jaguar Land Rover, Thales and DSTL. In this way, there is a very large industrial oversight to this project.

In addition to the direct industrial oversight/collaboration mentioned above, there is also indirect dissemination to industry through web pages, conferences, seminars, publications and importantly a road map for 3D printed microwave circuits written within the project and disseminated widely.

It can be seen that the potential for new, novel circuits is considerable, such circuits will improve system performance in a number of industries. This programme of research aims to develop the technology and principles of 3D printing and importantly inform industry of the advantages and practical ways forward in using the new manufacturing technique. By disseminating the principles as well as example demonstrators we aim to provide a unique route to impact with rapid take up of 3D printing where it is appropriate. It should be noted although we have given examples above of industrial interest, the manufacturing will be of considerable interest in a variety of microwave areas we are unable to comprehend at this time.


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Chen X (2021) Ring-Shaped D -Band E -Plane Filtering Coupler in IEEE Microwave and Wireless Components Letters

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Chen X (2021) E -Plane Waveguide Filtering Six-Port Junction in IEEE Transactions on Microwave Theory and Techniques

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Chen X (2022) Subterahertz Filtering Six-Port Junction in IEEE Transactions on Microwave Theory and Techniques

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Gao Y (2020) Substrate Integrated Waveguide Filter-Amplifier Design Using Active Coupling Matrix Technique in IEEE Transactions on Microwave Theory and Techniques

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Gao Y (2019) An x-band waveguide orthomode transducer with integrated filters in Microwave and Optical Technology Letters

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Le H (2022) Laser precession machining of cross-shaped terahertz bandpass filters in Optics and Lasers in Engineering

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Mohammed A (2020) 3D printed coaxial microwave resonator sensor for dielectric measurements of liquid in Microwave and Optical Technology Letters

Description The research work has tested and pushed the boundary of the utilisation of additive manufacturing technologies in waveguide devices in terms of the operation frequency and allowable geometry. A number of devices have been demonstrated.
The research has identified key advantages as well as main limiting factors of additive manufacturing technologies for mm-wave and terahertz devices.
Exploitation Route De-risk the technology and raise the TRL.
Demonstrate capability.
Sectors Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Electronics,Manufacturing, including Industrial Biotechology

Description We have seen significantly increasing interests from the industry (microwave and space related) sectors as well as from academia in this new manufacturing technology. In particular, we have seen more funding opportunities coming up from space sectors. The increasing adoption of the technology in space is imminent.
First Year Of Impact 2020
Sector Aerospace, Defence and Marine
Impact Types Economic

Description 4000131423/20/NL/FE Next Generation Temperature Compensated High Power Filters Based on Novel Materials
Amount € 599,042 (EUR)
Funding ID 4000131423/20/NL/FE 
Organisation European Space Agency 
Sector Public
Country France
Start 08/2020 
End 05/2023
Description Open Space Innovation Platform (OSIP)
Amount £51,772 (GBP)
Funding ID 4000136425/21/NL/GLC/my 
Organisation European Space Agency 
Sector Public
Country France
Start 08/2021 
End 09/2025
Description TALENT: Technician Led Equipment Fund
Amount £5,580 (GBP)
Organisation United Kingdom Research and Innovation 
Department Research England
Sector Public
Country United Kingdom
Start 11/2020 
End 02/2021
Description 3D Microprint GmbH 
Organisation 3D Microprint
Country Germany 
Sector Private 
PI Contribution Our group contributes in designing of microwave components to be manufactured using 3D printing technology.
Collaborator Contribution Our partner 3DMicroPrint GmbH mainly contributes in manufacturing of devices using the state-of-the-art 3D printing machines with high precision and accuracy.
Impact Many devices have been designed, fabricated and tested.
Start Year 2016
Description Airbus Defence and Space 
Organisation Airbus Group
Department Airbus Defence and Space UK
Country United Kingdom 
Sector Private 
PI Contribution Our group will contribute with expertise in microwave engineering to develop waveguide components for satellite communication system.
Collaborator Contribution Airbus Defence and Space are interested in passive components for constellations of geostationary high throughput satellites. They will provide us with specification for devices.
Impact Work will commence soon.
Start Year 2018
Description Collaboration with Flann Microwave Ltd 
Organisation Flann Microwave Ltd
Country United Kingdom 
Sector Private 
PI Contribution We provide a potentially new manufacture solution to some of the company's products.
Collaborator Contribution The company provides the industry perspective in terms of applications and products of interest and some insightful design tips.
Impact Joint publication; Potentially a bid for the IAA scheme.
Start Year 2021
Description Elite Antennas Ltd 
Organisation Elite Antennas
Country United Kingdom 
Sector Private 
PI Contribution Our group contributes with expertise in microwave engineering to design components such as orthomode transducers for satellite communications.
Collaborator Contribution Our partner provides us with specification for components used for Ka-band satellite communications.
Impact A novel orthomode transducer has been developed and tested.
Start Year 2017
Description Filtronic 
Organisation Filtronic
Country United Kingdom 
Sector Private 
PI Contribution Our group contributed with expertise in design of components specified by our partner Filtronic.
Collaborator Contribution Our partner Filtronic provided us with specification for a component used in communication systems.
Impact A component used in communications systems has been designed, fabricated and tested.
Start Year 2018
Description Fraunhofer Institute 
Organisation Fraunhofer Society
Department Fraunhofer Institute FKIE
Country Germany 
Sector Academic/University 
PI Contribution Our group contributes in designing microwave components to be manufactured using emerging technologies.
Collaborator Contribution Our partner contributes in manufacturing devices using emerging technologies such as 3D screen printing.
Impact A device at 300 GHz has been designed and fabricated using 3D screen printing technology.
Start Year 2016
Description Huawei Group 
Organisation Huawei Technologies
Country China 
Sector Private 
PI Contribution Our group will contribute with expertise in microwave engineering to design components for 5G communication system.
Collaborator Contribution Our partner will provide us with specification for components used in 5G communications systems.
Impact Work will commence soon.
Start Year 2018
Description InnovaSec Ltd 
Organisation InnovaSec
Country United Kingdom 
Sector Private 
PI Contribution collaboration to commence soon.
Collaborator Contribution collaboration to commence soon.
Impact collaboration to commence soon.
Start Year 2018
Description Jaguar Land Rover 
Organisation Jaguar Land Rover Automotive PLC
Department Jaguar Land Rover
Country United Kingdom 
Sector Private 
PI Contribution Collaboration to commence soon.
Collaborator Contribution Collaboration to commence soon.
Impact Collaboration to commence soon.
Start Year 2016
Description Teratech Components Ltd 
Organisation Teratech Components
Sector Private 
PI Contribution Our group contributes with expertise in microwave components to design 3D printed frequency multipliers at frequencies above 100 GHz.
Collaborator Contribution Teratech Components Ltd manufacture and supply diodes operating at high frequencies to be used in multiplier circuit.
Impact A frequency multiplier operating above 100 GHz has been designed.
Start Year 2016
Description Invited Workshop speaker in European Microwave Conference 2020 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact 2020 EUMC
- Workshop/Short Course name: "Recent Advances in Additive Manufacturing of Microwave Components"
- Workshop Organiser: "Prof. Maurizio Bozzi ("
- Workshop Co-Organiser: "Prof. Cristiano Tomassoni ("
- Paper Identifier: "W29-2"
- Paper Title: "Microwave and millimetre-wave 3D printed waveguide filters"
Year(s) Of Engagement Activity 2020