Microwave ferrites Temex-Ceramics

In recent years due to success in the field of microwave electronics a lot of devices of different applications were produced. The prospects for future development of microwave systems with predetermined characteristics are mainly assigned by ferrite choise. However the choise of a material for a concrete application in microwave technique is a complicated task, as there are different requirements to different parts of microwave band. Among main characteristics of ferrites suitable for high frequencies are:

• At the expense of high specific electrical resistivity (ρ >10⁶ Ом·sm) ferrites are characterised by low dielectric losses at high frequencies tgδ=10^-2÷10^-4).
• Dielectric permittivity ε^' (about 10-15)
• Thermal stability in a wide temperature range
• The high activity is being determined by the value of minimal bias which is essential for required nominal parameters providing.
• Saturation magnetization, M _s; 4πM_s (400-5000 G)
• The width of resonance curve 2ΔH is one of the main parameters characterising properties of ferrites applied in high-frequency band. The yttrium-iron monocrystals exhibit the minimal value 2ΔH =0.3-0.5 Oe. The width of resonanse curve of polycrystalline ferrites varies from 30...40 to 800-1000 Oe.

The technical performance of devices on the base of ferrites mainly depends on operating principle, application, frequency band and power level. For many years Temex-Ceramics (1971, Bordeaux/France) is one of the world leaders in the field of high frequency materials development and manufacturing. In june 2012 Temex-Ceramics was introduced in Exxelia Group membership. This is a group of companies, supplying electronic parts for different industry fileds. The sales are being realized all over the world by officical distributors in Italy, Eastern Europe, Russia, India, Korea and others.

In 2008 "Lepcos" got a status of Temex-Ceramics official distributor.

Temex-Ceramics Ferrites can be successfully applied in circulators, isolators, phase-shifters, choppers and others.

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Application	Required characteristics	recommendations for materials choosing
Circulators of low power level	Low inserted losses,compactability, a wide frequency band, a wide nominal temperature range, high radiation directivity	The width of ferromagnetic resonance curve (2ΔH; ΔH eff) - minimal values; Dielectric permeability(ε') maximal value; Saturation magnetization (M s ) is determined in accordance with predermined frequency; Temperature coefficient(α) is minimal
Circulators of high power level	The power stability, low inserted lossses , thermal stability	The value characterising the width of spin wave line (ΔH k) must be high ; ΔH eff and ΔH should be close to the the value of ΔH k
Resonance-type isolator (working range - up to resonance)	low inserted losses, narrow -width frequency band	Effective width of resonance curve ΔH eff minimal; M s corresponds to frequency

General characteristics of Temex-Ceramics materials are listed in the table below.

Crystal structure	Temex-Ceramics part number	chemical composition	Recommended frequency band	Thermal stability	Power stability	Magnetic losses
Garnet	Y1xx	Y-Gd	1.55-10.90 GHz	**	*	*
Garnet	Y2xx	CVG	1.55-10.90 GHz	**	*	***
Garnet	Y3xx	Y-Al	0.34-6.20 GHz	*	*	**
Garnet	Y4xxx	Y-Al	1.55-6.20GHz	***	**	**
Гранат	Y7xx	Y-Gd-Al	0.34-6.20 GHz	*	**	*
Garnet	Y9xx	Y-Gd-Al with Co additive	0.34-10.90 GHz	**	***	*
Garnet	Dx	Y-Gd-Al with Dy additive	0.34-10.90 GHz	**	***	*
Spinel	Uxx	Mn-Mg	1.55-36 GHz	*	*	**
Spinel	Axxx	Li	6.20-40 GHz	***	*	***
Spinel	Nxxx	Ni	1.55-40 GHz	***	***	*

* bad; **good; ***excellent

Configurations

Temex-Ceramics ferrites are being produced on the base of pressed powder sintered at high temperatures. After thermal sintering the items can be smoothed and/or polished. Company produces items with different forms. Dimensional allowance at mechanical treatment is ±0,025 mm. In spite of standard variants of performance it is possible to produce cores in accoradance with sizes and customers drawings.

Standard variants of cores performance

Disk	Diameter: 1-55 mm
Plates	maximal size: 50.8 х 50.8 mm thickness: 0.5-3 mm
Triangles Rods	max diameter: 12mm max length: 90 mm
Composition	Ferrites and dielectric materials

Oredering Code	Configuration
D	Disk
T	Triangle
S	Plate

Dimensional allowance for all configurations are listed below.

Ordering code	Dimensional allowance (mm)	Dimensional allowance (inch)
Z	±0.200	±0.008
Y	±0.150	±0.006
X	±0.100	±0.004
W	±0.050	±0.002
V	±0.025	±0.001

TEMEX-CERAMICS ferrite materials

Тemex-Ceramics manufactures ferrites on the base of compounds with garnet and spinel structures. Yttrium-iron garnets are applied for production of different high-frequency devices operating in low border of high-frequency band. The great interest to ferrites with garnet structure, particularly, to yttrium garnet is explained by narrow line of ferromagnetic resonance absorption. Such materials are also characterised by small magnetic losses; relatively high magnetization; high thermalstability.Often ions of Cobalt and Rare-earth ions (Dy), (Gd) are introduced to materilas structure in order to improve material characteristics for increasing of ferrite stability to Power.

Materials on the base of yttrium iron garnets

Type	4πMs(G) ±5%	Тs(°С) ±5%	ΔH(Oe) ±20%	ΔH eff(Oe) ±20%	ΔH k(Oe) ±10%	ε ' ±5%	104 tanδ	Detailed information
Heat-resisting with narrow frequency band
Y4091	960	195	35	12	9	15.2	<2
YIG (Iron-Yttrium)
Y10	1790	280	45	4	2	15.3	<2
Y101	1820	280	20	4	2	15.4	<2
Y102	1800	280	30	4	2	15.3	<2
Y-Gd (Ittrium-Gadolinium)
The material can be applied when high thermal stability is required
Y11	1600	280	60	5	3	15.3	<2
Y12	1420	280	65	6	3	15.3	<2
Y13	1250	280	75	8	8	15.3	<2
Y14	1100	280	95	12	9	15.4	<2
Y15	900	280	140	18	11	15.4	<2
Y16	750	280	200	25	15	15.4	<2
CVG (Сalcium-Vanadium)
This materials range was specially developed for application in devices, where low inserted losses are required
Y220	1950	205	10	2	1	15.4	<2
Y218	1850	215	10	-	-	14.8	<2
Y216	1600	218	10	-	-	14.8	<2
Y215	1450	215	10	2	1	14.7	<2
Y212	1200	209	10	2	1	14.5	<2
Y211	1100	205	10	2	1	14.4	<2
Y210	1000	200	10	-	-	14.2	<2
Y209	900	180	10	2	1	14.1	<2
Y208	800	170	10	2	1	14.0	<2
Y-Al (Yttrium- Aluminium)
Due to a wide band of saturation magnetization values such materials can be applied in different high-frequency devices operating at low inserted losses
Y35	1200	225	40	4	2	15.3	<2
Y351	1200	225	22	4	2	14.9	<2
Y34	1030	210	40	4	2	14.8	<2
Y341	1030	210	22	4	2	14.8	<2
Y39	800	195	40	4	2	14.6	<2
Y391	800	195	22	4	2	14.6	<2
Y38	760	190	40	4	2	14.5	<2
Y381	760	190	22	4	2	14.5	<2
Y37	680	180	40	4	2	14.5	<2
Y371	680	180	22	4	2	14.5	<2
Y33	615	175	40	4	2	14.5	<2
Y331	615	175	22	4	2	14.5	<2
Y30	565	160	30	4	2	14.4	<2
Y32	420	135	30	4	2	14.4	<2
Y31	370	125	30	4	2	14.1	<2
Y36	290	115	25	4	2	14.1	<2
Y302	240	100	30	4	2	14.1	<2
Y-Gd-Al (Yttrium-Gadolinium- Aluminium)
The special feature of these materials is high thermal stability. They are suitable for application in devices of middle power level.
Y71	1020	235	60	7	5	15	<2
Y710	1020	240	75	9	7	15	<2
Y77	950	230	60	6	5	14.9	<2
Y780	830	235	60	6	5.5	14.8	<2
Y78	800	220	80	8	8	15	<2
Y708	800	260	140	15	15	15.2	<2
Y74	670	190	60	6	6	14.9	<2
Y72	540	175	60	6	6	14.6	<2
Y705	470	170	65	6	6	14.3	<2
Y75	400	160	65	6	6	14.3	<2
Y76	390	150	50	6	6	14.2	<2
Y-Gd-Al Co or Dy(Yttrium-Gadolinium-Aluminium with Co and Dy additives)
Materials are suitable for application in devices of high power level. These materials are characterised by good thermal stability.
Y918	1760	280	85	12	20	15	<2
Y91	1020	240	60	17	14	15.1	<2
Y86	830	270	95	34	25	15.4	<2
Y94	780	250	75	14	23	15.2	<2
Y908	780	250	85	14	29	15.2	<2
Y9081	780	250	120	14	35	15.2	<2
Fe-Y + Dy additives ( yttrium iron garnet with Dy additives)
Materials are suitable for application in devices with high power level and are characterised by increased thermal stability
D1	1400	270	110	34	16	15.5	<2
D5	1070	270	150	36	23	15.5	<2
D2	900	270	185	25	24	15.5	<2
D3	590	175	85	16	19	14.5	<2
D4	580	170	140	34	33	14.4	<2

Ferrite materials on the base of Mg spinel are characterised by small values of coercive field strength and also by low magnetic and dielectric losses that allows to use them in fields far from resonance area. cocernintg devices operating nerby resonance area the great is interest is attracted to materials on the base of Ni spinel. Such ferrites are characterised by a wide range of magnetization and high thermal stability. Ferrites on the base of Li spinel can be used in discrete phase shifters. Small values of coercive field strength and thermal stability in operating temperature range and a wide range of saturation magnetization values are characteristic for such materials.

Materials on the base od compunds with spinel structure

Type	4πMs(G) ±5%	Тs(°С) ±5%	ΔH(Oe) ±20%	ΔH eff(Oe) ±20%	ΔH k(oe) ±10%	ε ' ±5%	104 tanδ	Detailed information
Mn-Mg
Suitable for application in devices with low magnetic and dielectric losses.
U21	2400	275	290	6	4	13	<3
U20	2100	300	360	6	4	13	<3
U19	1900	280	350	6	4	13	<3
U33	1600	230	290	6	4	12.4	<3
Li (Lithium-Titanium-Zink)
These materials are used when manufacturing thermallly stable components operating in S-band. Ferrites А370 and А230 can be used in power electronics
A50	5000	450	170	4	3	15.3	<5
A500	4900	450	200	9	10	15.3	<5
A37	3700	565	400	4	3	16	<5
A370	3700	565	400	4	3	16	<5
A30	3000	555	450	4	3	16.4	<5
A28	2800	540	450	4	3	16.6	<5
A24	2450	390	250	4	3	16.8	<5
A23	2300	505	450	4	3	16.8	<5
A230	2300	505	450	9	8	16.7	<5