CA1301914C - Antenna coupler - Google Patents
Antenna couplerInfo
- Publication number
- CA1301914C CA1301914C CA000565664A CA565664A CA1301914C CA 1301914 C CA1301914 C CA 1301914C CA 000565664 A CA000565664 A CA 000565664A CA 565664 A CA565664 A CA 565664A CA 1301914 C CA1301914 C CA 1301914C
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- coupler
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- frequency
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Abstract
ANTENNA COUPLER
Abstract of the Invention An automatic antenna coupler is disclosed. The antenna coupler automatically matches the output impedance of a 50-ohm transmitter to the input impedance of a non-broad-band antenna, such as a whip, dipole or long wire. The resulting increase in transmit coupling efficiency provides greater radiative power than that available from an un-matched antenna.
Abstract of the Invention An automatic antenna coupler is disclosed. The antenna coupler automatically matches the output impedance of a 50-ohm transmitter to the input impedance of a non-broad-band antenna, such as a whip, dipole or long wire. The resulting increase in transmit coupling efficiency provides greater radiative power than that available from an un-matched antenna.
Description
~L3~ 4 .
ANTENNA COUP~ER
Background o~ the Invention The pre ent ~nvention relates to an ant~nna coupler for use ln ~ RF (Radio ~r~quency) transmitting system.
The two ~a~or componen~ of a transmitting station are ~he transmitter and the antenna. The transmitter generates a high power RF ~ignal and the antenna receive~ this signal and radiates it. To lnsure that most of the RF power is properly coupled ko th2 antenna, the antenna must match the output impedance o~ the transmitter. Unfortunately, ir.
broadband ~F 6ystems, unless a large elab~rate antenna system i ~mployed, the an~enna will not provide a good impedanc~ ~atch over the en~lr~ frequency range. There-~ore, for s~mple ~ntenna installatlons, a device called an antenna coupler must be use~ to maximize the radiated power of the ~tation.
An ant~nna coupler is ~ varlabl~ impedance matching network desi~ned to match the $mpedance o~ the antenna ~o that of the transmitter. It i~ usually compo ed o~ an L~network or a ~-network using &ervo driven, variable c~paci~ors and roller inductor6, although more mod~rn implementa~ions use digitally ~witched ~n~uc~or and capaci~or banks. They also i~lud~ ~imple impedance de~ectors and con~rol logic t~
~acllitat~ automati~ tuninga A-44957/.SEB
~3~
ANTENNA COUP~ER
Background o~ the Invention The pre ent ~nvention relates to an ant~nna coupler for use ln ~ RF (Radio ~r~quency) transmitting system.
The two ~a~or componen~ of a transmitting station are ~he transmitter and the antenna. The transmitter generates a high power RF ~ignal and the antenna receive~ this signal and radiates it. To lnsure that most of the RF power is properly coupled ko th2 antenna, the antenna must match the output impedance o~ the transmitter. Unfortunately, ir.
broadband ~F 6ystems, unless a large elab~rate antenna system i ~mployed, the an~enna will not provide a good impedanc~ ~atch over the en~lr~ frequency range. There-~ore, for s~mple ~ntenna installatlons, a device called an antenna coupler must be use~ to maximize the radiated power of the ~tation.
An ant~nna coupler is ~ varlabl~ impedance matching network desi~ned to match the $mpedance o~ the antenna ~o that of the transmitter. It i~ usually compo ed o~ an L~network or a ~-network using &ervo driven, variable c~paci~ors and roller inductor6, although more mod~rn implementa~ions use digitally ~witched ~n~uc~or and capaci~or banks. They also i~lud~ ~imple impedance de~ectors and con~rol logic t~
~acllitat~ automati~ tuninga A-44957/.SEB
~3~
2 61051-~16~
Each time the frequency is chanyed, the antenna coupler must go through a tune sequence. This involves setting the network to a known home position, and then while transmitting, changing one of the elements in one direction until a desired conclition takes pla~e, as for instance, the sign of the phase changing. Then another element of the network is changed in a desired direc~ion until its desired condition occurs, bringing the coupler to a closer ma~ch. This process is repeated until the desired impedance match is obtained and the process stops. Normally, the tune sequence takes a few seconds to complete. Unfortunately, the tune sequence of such tuners is too slow to track FM CW signals (or swept signals) or to avoid detection by clirection finding equipment in a military environment.
Summary of ~he Invention It is an object of the invention to provide for an automatic antenna coupler for use in swept high frequency (HF) transmission systems.
It is a more particular object of the present invention to provide for an automatic antenna coupler which :Ls suitable fos use in a range from 1.6-30 MHz.
The present invention provides an automatic antenna coupling capability and includes adjustable impedance matching means for matching the output impedance of a transmitter to the input impedance o~ a non-broadband antenna. In one preferred embodiment, the coupler further includes means for tracking the frequency of a s~ept transmitted signal and mean~ responsive to the tracked signal for automatically adjusting the adjustable ~3~
2a 61051-~16~
impedance matching means to provide proper lmpedance ma~ching.
Aceording to a broad aspect of the invention ~here is provided an antenna coupler comprisiny adjustable lmpedance matching network means for matching ~he ou-tput impedance o f a transmitter at a radio frequency (RF) input to the input impedance of a non-broadband antenna, means for tracking a swept, transmitted signa:L at sald RF
input, and processor means responsive to the tracked signal for automatically adjusting said impedance matching network means to provide an impedance match between said output impedance and said input impedance wherein said processor means includes means for dividing the swept frequency range into discrete bands, means for determining the frequency of said input signal to be matched for each of said bands, and for determining any changes in the frequency of said input signal, means for measuring and quantifying the value o~ the impedance itself at said antenna for each of the determined frequencies, and means for calculating the amount of adjuskment needed to match said output impedances and said input impedances based upon measured value of impadance for each of said determined frequencies, so as to provide an impedance match for each of said discrete bands.
According to another broad aspect of the invention there is provided an antenna coupler comprising ~3~
2b adjustable lnput impedance matching network means for matching the output impedance of a transmitter at a raclio frequency (RF) input to the input impedance of a non-broadband antenna, means for detecting changes in said output impedance when an RF signal is transmitted to said RF input, means for measuriny and quantifying khe value of the impedance itself at said antenna, means for calculating the amount of adjustment needed to match said output impedances and said input impedances based upo~
the measured value of impedance, means for rematching said output impedance to said input impedance if the detected changes vary from a certain predetermined value.
According to another broad aspect of the invention the~e is provided an antenna coupler comprising adjustable impedance matching network means for matching the output impedan~e of a transmitker at a radio frequency (RF) input to the input impedance of a non-broadband antenna, means for measuring and quantifying the impedance value itself of said antenna~
means for calculatiny the amount of adjustmen~ needed to match said output impedances and said input impedances based upon the measured impedance value, and means for adjusting said adjustable impedance matching network means to match said output and input impedances.
Other objects, features and advantages of the present invention will become apparent from the followiny ~etailed ~3~
Each time the frequency is chanyed, the antenna coupler must go through a tune sequence. This involves setting the network to a known home position, and then while transmitting, changing one of the elements in one direction until a desired conclition takes pla~e, as for instance, the sign of the phase changing. Then another element of the network is changed in a desired direc~ion until its desired condition occurs, bringing the coupler to a closer ma~ch. This process is repeated until the desired impedance match is obtained and the process stops. Normally, the tune sequence takes a few seconds to complete. Unfortunately, the tune sequence of such tuners is too slow to track FM CW signals (or swept signals) or to avoid detection by clirection finding equipment in a military environment.
Summary of ~he Invention It is an object of the invention to provide for an automatic antenna coupler for use in swept high frequency (HF) transmission systems.
It is a more particular object of the present invention to provide for an automatic antenna coupler which :Ls suitable fos use in a range from 1.6-30 MHz.
The present invention provides an automatic antenna coupling capability and includes adjustable impedance matching means for matching the output impedance of a transmitter to the input impedance o~ a non-broadband antenna. In one preferred embodiment, the coupler further includes means for tracking the frequency of a s~ept transmitted signal and mean~ responsive to the tracked signal for automatically adjusting the adjustable ~3~
2a 61051-~16~
impedance matching means to provide proper lmpedance ma~ching.
Aceording to a broad aspect of the invention ~here is provided an antenna coupler comprisiny adjustable lmpedance matching network means for matching ~he ou-tput impedance o f a transmitter at a radio frequency (RF) input to the input impedance of a non-broadband antenna, means for tracking a swept, transmitted signa:L at sald RF
input, and processor means responsive to the tracked signal for automatically adjusting said impedance matching network means to provide an impedance match between said output impedance and said input impedance wherein said processor means includes means for dividing the swept frequency range into discrete bands, means for determining the frequency of said input signal to be matched for each of said bands, and for determining any changes in the frequency of said input signal, means for measuring and quantifying the value o~ the impedance itself at said antenna for each of the determined frequencies, and means for calculating the amount of adjuskment needed to match said output impedances and said input impedances based upon measured value of impadance for each of said determined frequencies, so as to provide an impedance match for each of said discrete bands.
According to another broad aspect of the invention there is provided an antenna coupler comprising ~3~
2b adjustable lnput impedance matching network means for matching the output impedance of a transmitter at a raclio frequency (RF) input to the input impedance of a non-broadband antenna, means for detecting changes in said output impedance when an RF signal is transmitted to said RF input, means for measuriny and quantifying khe value of the impedance itself at said antenna, means for calculating the amount of adjustment needed to match said output impedances and said input impedances based upo~
the measured value of impedance, means for rematching said output impedance to said input impedance if the detected changes vary from a certain predetermined value.
According to another broad aspect of the invention the~e is provided an antenna coupler comprising adjustable impedance matching network means for matching the output impedan~e of a transmitker at a radio frequency (RF) input to the input impedance of a non-broadband antenna, means for measuring and quantifying the impedance value itself of said antenna~
means for calculatiny the amount of adjustmen~ needed to match said output impedances and said input impedances based upon the measured impedance value, and means for adjusting said adjustable impedance matching network means to match said output and input impedances.
Other objects, features and advantages of the present invention will become apparent from the followiny ~etailed ~3~
- 3 - 7~388-2 description when taken in conjunction with the accompanying draw-ings.
Brief Description of -the Drawings Fig. 1 depicts block diagram of an antenna coupler according to the present invention.
Fig. 2-10 depict schematic diagrams of -the an-tenna coupler depicted in Fig. 1. Figs~ 3-9 comprise parts "A" and "B"
and Fig. 10 comprises parts "A", "B" and "C".
Detailed Description of the Drawings The aspects of the automatic antenna coupler according to the present invention will now be described in conjunction with Figs. 1-10.
The automatic antenna coupler according to the presen-t invention is an automatically tuned network that, in one preferred embodiment, matches the output impedance of typically a 5~-ohm transmitter to the input impedance of a non-broadband antenna, such as a whip, dipole or long wire. The resulting increase in transmit coupling efficiency provides greater radia-ted power than that available from an unmatched antenna. The present invention is designed for use with any 1-150 watt ~F (high frequency) trans-mitter operating from 1.6 to 30 MHz.
Fig. 1 depicts a block diagram of an antenna coupler according to the present invention. In Fig. 1, an RF (radio frequency) input signal is input to a 4:1 impedance transformer 12. A suitable VSWR (voltage standing wave ratio) detector 1~
provides suitable detection of forward voltage 22, reflected vol tage 20, phase 1~ and frequency 16 of the RF input.
~ 34~
An A/D ccnverter 26 r~ceives the forward voltage signal 22, re~lected voltage ~ignal 20 and p~ase signal 18, and provides appropriate corresponding digi~al signals on lead 28 to micropro~essor 40.
Frequency counter 24 receives the rrequency detected signal on lead 16, and provides a suitable frequency signal to ~icr~processor 40 on lead 32.
Th~ present invention includes a suitab~e adjustable or adaptable matching network 30 which includes adjustable inductsrs 34 and adjustable capacitors 36. Matching network 30 ls co~trolled by co~trol signals on lead 42 from microprocessor 40. The control ~ignals on lead 42 include, in one e~bodiment, eigh~ capacitor leads and twelve induc-tor leads - ~ total of twen~y lines.
The reason most antenna couplers take so long to tune is the ~act that it is unknown how much an element needs to be changed. Therefore, it is changed incrementally in one direction until a predefined condition is met. If the coupler were implemented with digitally switched el~ments, and the desired value of the elements could be calculate~
~ccurately, then the antenna coupler tune sequence could be reduced to th~ time it takes to select those elements, l.e., the relay settling time. This i5 what ~he present lnvention accomplishes.
In on~ preferred embodiment, the coupler According to the present lnvention includes ~n ~-ne~work using relay Ewitched chunt cap~citor~ and series ~nductors. The RF
~ro~ the tr~n~mitter passes through a 4:1 RF transformer 12 tQ give ~ nominal ~mpedanee ~ ~2.5 ohms. Then it passes 30 through . . ~irec~ ional coupler ~r detector to the network 20. On~ of the import~nt aspects of the coupler is the dir~ction~l coupler 1~. The ~orward (22) and re~lected (20) ou~puts are ~ed ~o an accurat~ phase deteckor and the ~31D1~
measured pha~e ~nd amplltudes o~ the forward and reflected voltag~s ~re read into ~icroprocessor 40 with an A/D
converter 26. Consequently, micrDprocessor 40 has an accurate measurement of the impedance, and therefore can calculate the needed inductance to match the antenna 50.
In one ~mbodiment, t~e ~eries inductor section was composed of eleven binary weighted inductor~ connected in a parallel ~ashion. ~he large6t inductor was 82.0 uH. The inductance value ~ aelec~d by a b~nary number N. Therefore, the r~lationshlp between inductance and N is 82/N uH, and $nd~uctive re~ct~nce and N would be 82.0~w/N, where w is the ~requency in radians/secO
I~ the inductor was set at Nl and ~he inductive reactance ne~ds to be changed by dX, then the new value of ~, N2 would ~e determined ~y solving the following equatio~:
82.0E-6~w/N2 ~ 82.OE-6~w/Nl = dX
or:
N2 3 82.0E-6~w~Nl / (82.0E-6*w + dX*Nl) The pr~sent invention is a "smart" c~pler which can learn ~i.e., measure, correct ~nd store) the tuning character i6tics of an antenna for all ~requencies from 2 ~o 30 MHz in 0n8 6we~p of ~ tr~nsmitter. While tuned to a fixed fr~quency or ~ollowing a Chirp sweep, the coupler divides th~ 2-30 MHz ran~e ~nto disGret~ b~nd~ as narrow as 20 kHz, th~n lQarns and store~ the v~lu~s o~ the regu~red matching n~twork ~or e~ch b~nd. Typical tuning time during the learning process lc 100 mill$second~ per frequency band.
. A~ter learnin~, all tuning corr~c~lons are recalled from non-volatile ~emory ~nd wlll be completed in less than 20 ~illi6econd~ per fregu~ncy ~or ~oth sw~eps ~nd fixed Xrequencie~ (SS~/CW~, even when following widely spaced ~r~quency ~u~p~ or ~ops. ~ the antenna characteristics .
.~ .
change tdue to 1ce loading, 6alt, sag, damage, etc.) the coupler automatically rev~rts to the learn mode.
During the learning process, the present invention uses impedance ~et~c~or~ and a microprocessor algorit~m to measure the antenna impedance and compute the LC matching network required to match the an~enna to 50 ohms. Whenever ~ requency change ~5 detected, a built-in frequ2ncy ~ountQr ~easures the ~nput RF freguency and the micropro-ce~or check6 the tunin~ m~tch. If the antenna match chec~
10 ~how~ a VSW~ sreater than 2.~-1, the microprocessor 40 will ad~u~t the ~atchlng network to reduce ~he VSWR ~o less than 1.5:1. The inductor6 and capacitors are switched into the matching network ~y relays controlled by ~he microproces-60r. Because the microprocessor computes the inductance and capacitance based on impedance measurements, fewer steps are required to tune. Iterative search methods 5uch as the common "return to home and search for 50 oh~s"
technique are not used, greatly reducing tuning time and relay chatter. To extend relay life, the relays are cold-switched by momentarily PIN-diode-switching the input RF to an internal 50 ohm dummy load during tuning operations.
Antennas of v~ry high VSWR will be ma~ched as closely as possible to 50 ohms, limited only ~y the coupler's ~uning 21ement6. When antenna VSWRs exceed 10:1, the match prQsented ~o the ~ransmi~ker may exceed 2.5:1.
The pressnt invention can al~o be used to tune an antenna ln the receivo mode. On a previously learned antenna, the transmi tt~r can s~nd a recsive ~re~uency command to the . antenn~ coupler. The coupler will rec~ll the ma~ched netwsrk ~ettlngs ~rom memory and tuns the antenna to that ~r~guancy without ~ tr~nsm~t tune ~equence.
Figs. 2, 3 and 4 depict schematic diagrams of the antenna coupler which show the aspects of ~he adjustable matching network 30 of Fig. 1.
Figs. 5-10 depict 6chematlc diagrams of the antenna tuner control of Fig~ 1.
The components of Fi~s. 2-10 are well known in the prior ~rt, and consequently the operation of those schematic dlagrams need not be described in any great detail.
Brief Description of -the Drawings Fig. 1 depicts block diagram of an antenna coupler according to the present invention.
Fig. 2-10 depict schematic diagrams of -the an-tenna coupler depicted in Fig. 1. Figs~ 3-9 comprise parts "A" and "B"
and Fig. 10 comprises parts "A", "B" and "C".
Detailed Description of the Drawings The aspects of the automatic antenna coupler according to the present invention will now be described in conjunction with Figs. 1-10.
The automatic antenna coupler according to the presen-t invention is an automatically tuned network that, in one preferred embodiment, matches the output impedance of typically a 5~-ohm transmitter to the input impedance of a non-broadband antenna, such as a whip, dipole or long wire. The resulting increase in transmit coupling efficiency provides greater radia-ted power than that available from an unmatched antenna. The present invention is designed for use with any 1-150 watt ~F (high frequency) trans-mitter operating from 1.6 to 30 MHz.
Fig. 1 depicts a block diagram of an antenna coupler according to the present invention. In Fig. 1, an RF (radio frequency) input signal is input to a 4:1 impedance transformer 12. A suitable VSWR (voltage standing wave ratio) detector 1~
provides suitable detection of forward voltage 22, reflected vol tage 20, phase 1~ and frequency 16 of the RF input.
~ 34~
An A/D ccnverter 26 r~ceives the forward voltage signal 22, re~lected voltage ~ignal 20 and p~ase signal 18, and provides appropriate corresponding digi~al signals on lead 28 to micropro~essor 40.
Frequency counter 24 receives the rrequency detected signal on lead 16, and provides a suitable frequency signal to ~icr~processor 40 on lead 32.
Th~ present invention includes a suitab~e adjustable or adaptable matching network 30 which includes adjustable inductsrs 34 and adjustable capacitors 36. Matching network 30 ls co~trolled by co~trol signals on lead 42 from microprocessor 40. The control ~ignals on lead 42 include, in one e~bodiment, eigh~ capacitor leads and twelve induc-tor leads - ~ total of twen~y lines.
The reason most antenna couplers take so long to tune is the ~act that it is unknown how much an element needs to be changed. Therefore, it is changed incrementally in one direction until a predefined condition is met. If the coupler were implemented with digitally switched el~ments, and the desired value of the elements could be calculate~
~ccurately, then the antenna coupler tune sequence could be reduced to th~ time it takes to select those elements, l.e., the relay settling time. This i5 what ~he present lnvention accomplishes.
In on~ preferred embodiment, the coupler According to the present lnvention includes ~n ~-ne~work using relay Ewitched chunt cap~citor~ and series ~nductors. The RF
~ro~ the tr~n~mitter passes through a 4:1 RF transformer 12 tQ give ~ nominal ~mpedanee ~ ~2.5 ohms. Then it passes 30 through . . ~irec~ ional coupler ~r detector to the network 20. On~ of the import~nt aspects of the coupler is the dir~ction~l coupler 1~. The ~orward (22) and re~lected (20) ou~puts are ~ed ~o an accurat~ phase deteckor and the ~31D1~
measured pha~e ~nd amplltudes o~ the forward and reflected voltag~s ~re read into ~icroprocessor 40 with an A/D
converter 26. Consequently, micrDprocessor 40 has an accurate measurement of the impedance, and therefore can calculate the needed inductance to match the antenna 50.
In one ~mbodiment, t~e ~eries inductor section was composed of eleven binary weighted inductor~ connected in a parallel ~ashion. ~he large6t inductor was 82.0 uH. The inductance value ~ aelec~d by a b~nary number N. Therefore, the r~lationshlp between inductance and N is 82/N uH, and $nd~uctive re~ct~nce and N would be 82.0~w/N, where w is the ~requency in radians/secO
I~ the inductor was set at Nl and ~he inductive reactance ne~ds to be changed by dX, then the new value of ~, N2 would ~e determined ~y solving the following equatio~:
82.0E-6~w/N2 ~ 82.OE-6~w/Nl = dX
or:
N2 3 82.0E-6~w~Nl / (82.0E-6*w + dX*Nl) The pr~sent invention is a "smart" c~pler which can learn ~i.e., measure, correct ~nd store) the tuning character i6tics of an antenna for all ~requencies from 2 ~o 30 MHz in 0n8 6we~p of ~ tr~nsmitter. While tuned to a fixed fr~quency or ~ollowing a Chirp sweep, the coupler divides th~ 2-30 MHz ran~e ~nto disGret~ b~nd~ as narrow as 20 kHz, th~n lQarns and store~ the v~lu~s o~ the regu~red matching n~twork ~or e~ch b~nd. Typical tuning time during the learning process lc 100 mill$second~ per frequency band.
. A~ter learnin~, all tuning corr~c~lons are recalled from non-volatile ~emory ~nd wlll be completed in less than 20 ~illi6econd~ per fregu~ncy ~or ~oth sw~eps ~nd fixed Xrequencie~ (SS~/CW~, even when following widely spaced ~r~quency ~u~p~ or ~ops. ~ the antenna characteristics .
.~ .
change tdue to 1ce loading, 6alt, sag, damage, etc.) the coupler automatically rev~rts to the learn mode.
During the learning process, the present invention uses impedance ~et~c~or~ and a microprocessor algorit~m to measure the antenna impedance and compute the LC matching network required to match the an~enna to 50 ohms. Whenever ~ requency change ~5 detected, a built-in frequ2ncy ~ountQr ~easures the ~nput RF freguency and the micropro-ce~or check6 the tunin~ m~tch. If the antenna match chec~
10 ~how~ a VSW~ sreater than 2.~-1, the microprocessor 40 will ad~u~t the ~atchlng network to reduce ~he VSWR ~o less than 1.5:1. The inductor6 and capacitors are switched into the matching network ~y relays controlled by ~he microproces-60r. Because the microprocessor computes the inductance and capacitance based on impedance measurements, fewer steps are required to tune. Iterative search methods 5uch as the common "return to home and search for 50 oh~s"
technique are not used, greatly reducing tuning time and relay chatter. To extend relay life, the relays are cold-switched by momentarily PIN-diode-switching the input RF to an internal 50 ohm dummy load during tuning operations.
Antennas of v~ry high VSWR will be ma~ched as closely as possible to 50 ohms, limited only ~y the coupler's ~uning 21ement6. When antenna VSWRs exceed 10:1, the match prQsented ~o the ~ransmi~ker may exceed 2.5:1.
The pressnt invention can al~o be used to tune an antenna ln the receivo mode. On a previously learned antenna, the transmi tt~r can s~nd a recsive ~re~uency command to the . antenn~ coupler. The coupler will rec~ll the ma~ched netwsrk ~ettlngs ~rom memory and tuns the antenna to that ~r~guancy without ~ tr~nsm~t tune ~equence.
Figs. 2, 3 and 4 depict schematic diagrams of the antenna coupler which show the aspects of ~he adjustable matching network 30 of Fig. 1.
Figs. 5-10 depict 6chematlc diagrams of the antenna tuner control of Fig~ 1.
The components of Fi~s. 2-10 are well known in the prior ~rt, and consequently the operation of those schematic dlagrams need not be described in any great detail.
Claims (12)
1. An antenna coupler comprising adjustable impedance matching network means for matching the output impedance of a transmitter at a radio frequency (RF) input to the input impedance of a non-broadband antenna, means for tracking a swept, transmitted signal at said RF
input, and processor means responsive to the tracked signal for automatically adjusting said impedance matching network means to provide an impedance match between said output impedance and said input impedance wherein said processor means includes means for dividing the swept frequency range into discrete bands, means for determining the frequency of said input signal to be matched for each of said bands, and for determining any changes in the frequency of said input signal, means for measuring and quantifying the value of the impedance itself at said antenna for each of the determined frequencies, and means for calculating the amount of adjustment needed to match said output impedances and said input impedances based upon measured value of impedance for each of said determined frequencies, so as to provide an impedance match for each of said discrete bands.
input, and processor means responsive to the tracked signal for automatically adjusting said impedance matching network means to provide an impedance match between said output impedance and said input impedance wherein said processor means includes means for dividing the swept frequency range into discrete bands, means for determining the frequency of said input signal to be matched for each of said bands, and for determining any changes in the frequency of said input signal, means for measuring and quantifying the value of the impedance itself at said antenna for each of the determined frequencies, and means for calculating the amount of adjustment needed to match said output impedances and said input impedances based upon measured value of impedance for each of said determined frequencies, so as to provide an impedance match for each of said discrete bands.
2. The coupler as in Claim 1 wherein the range of said swept transmitted signal is approximately 1.6 MHz to 30 MHz.
3. The coupler as in Claim 1 wherein the range of said swept transmitted signal is approximately 1.6 MHz to 16 MHz.
4. The coupler as in Claim 1 wherein said processor means includes means for storing said values of the required impedance for each of said discrete bands, and means for recalling said stored values for each of said discrete bands.
5. An antenna coupler comprising adjustable input impedance matching network means for matching the output impedance of a transmitter at a radio frequency (RF) input to the input impedance of a non-broadband antenna, means for detecting changes in said output impedance when an RF signal is transmitted to said RF input, means for measuring and quantifying the value of the impedance itself at said antenna, means for calculating the amount of adjustment needed to match said output impedances and said input impedances based upon the measured value of impedance, means for rematching said output impedance to said input impedance if the detected changes vary from a certain predetermined value.
6. The coupler as in Claim 5 wherein said transmitted signal is a fixed frequency RF signal.
7. The coupler as in Claim 5 wherein said transmitted signal is a swept transmitted signal.
8. An antenna coupler comprising adjustable impedance matching network means for matching the output impedance of a transmitter at a radio frequency (RF) input to the input impedance of a non-broadband antenna, means for measuring and quantifying the impedance value itself of said antenna, means for calculating the amount of adjustment needed to match said output impedances and said input impedances based upon the measured impedance value, and means for adjusting said adjustable impedance matching network means to match said output and input impedances.
9. The coupler as in Claim 8 wherein said transmitted frequency is a fixed RF frequency.
10. The coupler as in Claim 8 wherein said transmitted frequency is a swept transmitted RF signal and wherein said processor means includes means for dividing said swept frequency range into discrete bands.
11. The coupler as in Claim 10 including storage means for storing values representing the calculated amount of adjustment for each of said discrete bands.
12. The coupler as in Claim 11 including means for recalling said stored values for each of said discrete bands.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000565664A CA1301914C (en) | 1988-05-02 | 1988-05-02 | Antenna coupler |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000565664A CA1301914C (en) | 1988-05-02 | 1988-05-02 | Antenna coupler |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1301914C true CA1301914C (en) | 1992-05-26 |
Family
ID=4137952
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000565664A Expired - Lifetime CA1301914C (en) | 1988-05-02 | 1988-05-02 | Antenna coupler |
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| Country | Link |
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| CA (1) | CA1301914C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2151921A1 (en) * | 2008-08-07 | 2010-02-10 | Epcos AG | Dynamic impedance matching network and method for matching an impedance between a source and a load |
-
1988
- 1988-05-02 CA CA000565664A patent/CA1301914C/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2151921A1 (en) * | 2008-08-07 | 2010-02-10 | Epcos AG | Dynamic impedance matching network and method for matching an impedance between a source and a load |
| WO2010015550A1 (en) * | 2008-08-07 | 2010-02-11 | Epcos Ag | Dynamic impedance matching network and method for matching an impedance between a source and a load |
| US8542078B2 (en) | 2008-08-07 | 2013-09-24 | Epcos Ag | Dynamic impedance matching network and method for matching an impedance between a source and a load |
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