<PAGE>
                                                                    EXHIBIT 10.4


                                    SUBLEASE


         This Sublease (this "SUBLEASE") is entered into between Vari-L Company,
Inc., a Colorado corporation ("SUBLESSOR") and Olin Acquisition Corporation, a
Delaware corporation ("SUBLESSEE") as of March 31, 2003.

         1. SUBLEASED PREMISES. Sublessor hereby subleases to Sublessee, upon
the terms and conditions set forth herein, certain premises (the "SUBLEASED
PREMISES") consisting of the entire premises leased by Sublessor pursuant to
that certain lease dated March 12, 1997 (the "MASTER LEASE"), between Five K
Investments, as landlord (the "MASTER LESSOR"), and Sublessor, as tenant, with
respect to premises located at 4895 Peoria St., Denver, Colorado. A true,
correct and complete copy of the Master Lease is attached hereto as EXHIBIT A.
In connection with its use of the Subleased Premises, Sublessee shall also have
the non-exclusive right to use the areas described in the Master Lease as common
or shared areas.

         2. TERM. The term of this Sublease shall commence on the "CLOSING" as
defined in Section 1.1 of that certain Asset Purchase Agreement, dated December
2, 2002, by and among Sirenza Microdevices, Inc., Olin Acquisition Corporation
and Vari-L Company, Inc. (the "APA"), provided Sublessor has theretofore
obtained the consent of Master Lessor (the "COMMENCEMENT DATE"). The term,
subject to the earlier termination of the Master Lease or the sooner termination
of this Sublease pursuant to its terms, shall continue until June 30, 2003 (the
"TERMINATION DATE"). Sublessor will obtain the written consent of Master Lessor
to this Sublease in the form attached hereto as EXHIBIT B or other form
acceptable to Master Lessor, and reasonably acceptable to Sublessor and
Sublessee. Sublessee shall cooperate with Sublessor in obtaining the written
consent to the Sublease by Master Lessor.

         3. SUBLEASE RENT AND DEPOSIT.

            (a) BASE RENT. Sublessee shall pay Sublessor as rent for the
Subleased Premises ("BASE RENT") for each month during the period from the
Commencement Date to and including the Termination Date, the base rent payable
under the Master Lease. The first installment of Base Rent shall be due and
payable on the Commencement Date and on the first (1st) day of each month
thereafter. Base Rent shall be paid without any deduction or offset and without
prior notice or demand, at the address indicated by Sublessor from time to time.
The Base Rent for any period which is for less than one (1) month of the Term
shall be prorated.

            (b) ADDITIONAL RENT. In addition to Base Rent, Sublessee shall also
pay to Sublessor the entirety of all other costs payable by Sublessor under the
Master Lease, except for any costs for services, repairs or maintenance which
are not made at the request or for the benefit of Sublessee ("ADDITIONAL RENT").
In addition, at all times during the term of this Sublease, Sublessor shall
maintain direct contracts, in Sublessor's own name, with the relevant utility
provider, for the provision of any utilities to the Premises, including, without
limitation, for utilities such as electricity, water and heating. Sublessor
shall invoice Sublessee for the costs of the utilities provided under such
contracts, and Sublessee shall pay such amounts as Additional Rent pursuant to
the terms of this Section 3.(b). Additional Rent shall be payable to Sublessor
as and when payments are due from Sublessor pursuant to the Master Lease, but at

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<PAGE>

least five (5) business days prior to the date Sublessor must pay such amounts
to Master Lessor. Sublessee shall further pay to Sublessor as Additional Rent
any costs and expenses applicable to the Sublease Premises which are paid
directly by Sublessor, including, but not limited to, utilities, personal
property taxes and real property taxes; provided, however, that Sublessee shall
have no obligation with respect to any of such costs which are incurred solely
for the benefit of Sublessor. Base Rent and Additional Rent hereinafter
collectively shall be referred to as "RENT." Sublessee shall be entitled to, and
benefit from, any rental abatement granted Sublessor under the Master Lease for
whatever reason to the extent that such abatement relates to the Subleased
Premises and the term of this Sublease.

         4. USE; COMPLIANCE WITH LAWS; RULES. Sublessee may use the Subleased
Premises only for the uses set forth in the Master Lease. Sublessee shall
promptly observe and comply with all laws with respect to Sublessee's use of the
Subleased Premises; provided, however, that Sublessee shall not be required to
comply with any laws requiring the construction of alterations in the Subleased
Premises, unless due to Sublessee's particular use of the Subleased Premises as
distinct from the uses of the Subleased Premises prior to the Commencement Date
or required due to any alterations, additions or improvements made or proposed
by Sublessee. Sublessee shall not do or permit anything to be done in, about or
with respect to the Subleased Premises which would (a) injure the Subleased
Premises, (b) vibrate, shake, overload, or impair the efficient operation of the
Premises or the building systems located therein or (c) otherwise violate the
Master Lease.

         5. INSURANCE. In the event Master Lessor requires Sublessee to do so,
Sublessee shall obtain and keep in full force and effect during the term of this
Sublease, at Sublessee's sole cost, the insurance that Sublessor is required to
maintain as "tenant" under the Master Lease, and such policies shall name each
Sublessor and Master Lessor as an "additional insured." Upon request, Sublessee
shall promptly deliver certificates evidencing such insurance to Sublessor
and/or Master Lessor.

         6. TAXES. Sublessee shall pay before delinquency all taxes imposed
against Sublessee's personal property in the Subleased Premises allocable to the
term of this Sublease.

         7. SUBROGATION. The waiver of subrogation provisions set forth in the
Master Lease shall be deemed a three-party agreement binding among and inuring
to the benefit of Sublessee, Sublessor and Master Landlord, by reason of its
consent to this Sublease.

         8. INDEMNITY. Each party shall defend, indemnify, protect and hold
harmless the other from and against any and all liability, loss, claim, damage
and cost (including attorneys' fees) to the extent due to the negligence or
willful misconduct of the indemnifying party or its agents, employees or
contractors or the indemnifying party's violation of the terms of this Sublease.
This indemnification shall survive the termination of this Sublease.

         9. HAZARDOUS MATERIALS. Sublessee shall not, without the prior written
consent of Sublessor and Master Lessor, use, store, transport or dispose of any
Hazardous Material in or about the Subleased Premises, except for Hazardous
Materials of a type and in amounts used by Sublessor in the Premises prior to
the Commencement Date. In the event Sublessee is using Hazardous Materials at
the Subleased Premises, Sublessee, at its sole cost, shall comply with all

                                       2
<PAGE>

laws relating to its use of Hazardous Materials and any provisions of the Master
Lease pertaining to Hazardous Materials. If Hazardous Materials stored, used,
disposed of, or released on or about the Subleased Premises by Sublessee or its
agents or employees result in contamination of the Subleased Premises or the
water or soil thereunder, then Sublessee shall promptly take any and all action
necessary to clean up such contamination as required by law and any other action
specified under the Master Lease. Except as otherwise set forth in the APA,
Sublessee shall indemnify, defend, protect and hold Sublessor and Master Lessor
and each of their officers, directors, employees, successors and assigns
harmless from and against, all losses, damages, claims, costs and liabilities,
including attorneys' fees and costs, arising out of Sublessee's use, discharge,
disposal, storage, transport, release or emission of Hazardous Materials on or
about the Premises during the term of this Sublease. Unless otherwise defined in
the Master Lease, "HAZARDOUS MATERIALS" shall mean any material or substance
that is now or hereafter designated by any applicable governmental authority to
be, or regulated by any applicable governmental authority as, radioactive,
toxic, hazardous or otherwise a danger to health, reproduction or the
environment.

         10. REPAIRS. Sublessor shall deliver the Subleased Premises to
Sublessee in its current, "as is" condition. Sublessee agrees that (i) Sublessor
has made no representation or warranty of any kind or nature respecting the
Sublease Premises, their condition or suitability for Sublessee's use, except as
set forth in the APA, and (ii) Sublessee agrees to accept the Subleased Premises
in "as is" condition, without any obligation on the part of Sublessor to modify,
improve or otherwise prepare the Sublease Premises for Sublessee's occupancy.
Sublessor shall continue to perform the repairs and maintenance obligations
required of the Tenant under the Master Lease, and except where caused by the
negligence or willful misconduct of Sublessor, any costs of such repairs and
maintenance shall be paid by Sublessee to Sublessor as Additional Rent.

         11. ALTERATIONS. No alterations or improvements shall be made to the
Subleased Premises without the prior written consent of Sublessor and Master
Lessor in accordance with the provisions of the Master Lease.

         12. Intentionally omitted.

         13. LIEN; SECURITY INTEREST. Sublessor shall have no security interest
or lien on any item of Sublessee's trade fixtures, furniture, equipment and
other personal property ("SUBLESSEE'S PROPERTY"). Within ten (10) days after
Sublessee's request, Sublessor shall execute documents reasonably acceptable to
both parties to evidence Sublessor's waiver of any right, title, lien, or
interest in Sublessee's Property. Sublessor waives any right of distraint,
distress for rent or "landlord's lien" that may arise at law.

         14. CASUALTY; CONDEMNATION. If all or any part of the Subleased
Premises is taken by the exercise of the power of eminent domain or a voluntary
transfer in lieu thereof (a "CONDEMNATION") or damaged due to any peril
("CASUALTY"), this Sublease shall terminate to the extent the Master Lease
terminates with respect to the part of the Subleased Premises so taken or
damaged. In addition, to the extent that the Master Lease gives Sublessor any
right to terminate the Master Lease in the event of a casualty or condemnation
affecting the Premises, Sublessor shall be entitled to exercise or not exercise
such right in its sole and absolute discretion, and in such event, Sublessor
shall concurrently notify Sublessee of such election. If this Sublease is not

                                       3
<PAGE>

terminated following a Condemnation or Casualty, Sublessor shall make or use
reasonable efforts to cause Master Lessor to make all repairs and alterations
that are reasonably necessary to restore that portion of the Subleased Premises
so taken or damaged, and Rent shall be reduced to the extent Sublessor's rent
under the Master Lease is abated with respect to such Condemnation of the
Subleased Premises or Casualty affecting the Subleased Premises. All
Condemnation proceeds shall be shared with Sublessee to the extent applicable to
the Subleased Premises and Sublessee's share of the Shared Areas.

         15. ASSIGNMENT AND SUBLETTING. Sublessee may not assign this Sublease,
sublet the Subleased Premises or permit any use of the Subleased Premises by
another party (collectively, "TRANSFER"), without the prior written consent of
Sublessor, which consent may not be unreasonably withheld, and the prior written
consent of Master Lessor in accordance with terms of the Master Lease.
Sublessor's consent to one Transfer shall not constitute consent to a subsequent
transfer. Notwithstanding the foregoing, so long as Sirenza Microdevices, Inc.
continues to guaranty Sublessee's performance of its obligations under this
Sublease in accordance with the Guaranty (defined below), Sublessee may, without
Sublessor's prior written consent (but only after obtaining Master Lessor's
consent to the extent required under the Master Lease) and without constituting
an assignment or sublease hereunder, sublet the entirety of the Subleased
Premises or assign the Sublease to (a) an entity controlling, controlled by or
under common control with Sublessee, (b) a successor entity related to Sublessee
by merger, consolidation, or nonbankruptcy reorganization, or (c) a purchaser of
substantially all of Sublessee's assets located in the Subleased Premises.
Subject to the conditions contained in the immediately preceding sentence, a
sale or transfer of Sublessee's capital stock shall not be deemed an assignment,
subletting or any other transfer of the Sublease or the Subleased Premises.

         16. DEFAULT. Sublessee shall be in default of its obligations under
this Sublease if any of the following events occur: (a) Sublessee fails to pay
any Rent within five (5) days of when due; (b) Sublessee fails to perform any
term, covenant or condition of this Sublease (except those requiring payment of
Rent) and fails to cure such breach within the time frame specified in this
Sublease, or the Master Lease with respect to those provisions incorporated by
reference herein; or (c) Sublessee commits any other act or omission which
constitutes a default under the Master Lease, which has not been cured after
delivery of any written notice and passage of any applicable grace period
provided in the Master Lease.

         17. REMEDIES. In the event of any default by Sublessee, Sublessor shall
have the remedies provided in the Master Lease.

         18. RIGHT TO CURE DEFAULTS. If Sublessee fails to pay any sum of money
due hereunder, or fails to perform any other act on its part to be performed
hereunder, then Sublessor may, but shall not be obligated to, after passage of
any applicable notice and cure periods (except in the case of an emergency, in
which case no cure period is required), make such payment or perform such act.
All such sums paid, and all reasonable costs and expenses of performing any such
act, shall be deemed Additional Rent payable by Sublessee to Sublessor upon
demand.

         19. SURRENDER; HOLDOVER. Prior to expiration of this Sublease,
Sublessee shall remove all of its personal property and shall surrender the
Subleased Premises to Sublessor

                                       4
<PAGE>

broom clean, in the same condition as exists on the Commencement Date,
reasonable wear and tear, alterations that may be surrendered hereunder,
casualty, condemnation, and Hazardous Materials (except those for which
Sublessee is responsible under Section 9 of this Sublease or any applicable
provision of the Master Lease), excepted. If the Subleased Premises are not so
surrendered, then Sublessee shall be liable to Sublessor for all reasonable
costs actually incurred by Sublessor as a result of such failure by Sublessee.
In the event that Sublessee does not surrender the Subleased Premises upon the
expiration or earlier termination of this Sublease as to the Subleased Premises
as required above, Sublessee shall pay Sublessor holdover Base Rent in an amount
equal to the holdover rent specified in the Master Lease.

         20. ESTOPPEL CERTIFICATES. Within ten (10) calendar days after receipt
of written demand by either party, the other party shall execute and deliver to
the requesting party an estoppel certificate (a) certifying that this Sublease
is unmodified and in full force and effect or, if modified, the nature of such
modification; (b) acknowledging, to the best of the responding party's
knowledge, that there are no uncured defaults on the part of the requesting
party; and (c) certifying such other information as is reasonably required by
the requesting party.

         21. SUBORDINATION. This Sublease is subject and subordinate to all
present and future ground leases, underlying leases, mortgages, deeds of trust
or other encumbrances, and all renewals, modifications and replacements thereof
affecting any portion of the Subleased Premises.

         22. RIGHT OF ENTRY. Sublessor shall have the same right of entry into
the Subleased Premises as the Master Lessor under the Master Lease.

         23. LATE CHARGE. If Sublessee fails to pay to Sublessor any amount due
hereunder within five (5) days of when due, Sublessee shall pay Sublessor upon
demand a late charge equal to the amount of any late charge which is specified
under the Master Lease. In addition, Sublessee shall pay to Sublessor interest
on all amounts due, at the rate interest specified in the Master Lease from the
due date to and including the date of the payment.

         24. NOTICES. Any notice given under this Sublease shall be in writing
and shall be hand delivered or mailed (by certified mail, return receipt
requested, postage prepaid, or by overnight delivery), addressed as follows: (a)
if to Sublessee: 522 Almanor Avenue, Sunnyvale, CA 94085, Attn.: Chief Financial
Officer, with a copy to Wilson Sonsini Goodrich & Rosati, P.C., 650 Page Mill
Road Palo Alto, CA 94304, Attn: Steven V. Bernard and (b) if to Sublessor: 4895
Peoria St. Denver, CO 80239, Attn.: Chief Financial Officer, with a copy to
Cooley Godward LLP, 380 Interlocken Crescent, Suite 900, Broomfield, CO 80021,
Attn: James Linfield. Any notice shall be deemed to have been given when hand
delivered or, if mailed, three (3) business days after mailing.

         25. EFFECT OF CONVEYANCE. As used in this Sublease, the term
"SUBLESSOR" means the holder of a leasehold interest in the Premises pursuant to
the Master Lease. In the event of any assignment or transfer of the Premises by
Sublessor, then Sublessor, upon the transferee's assumption, in writing, of
Sublessor's obligations under this Sublease and the Master Lease, shall be and
hereby is entirely relieved of all covenants and obligations of Sublessor as to
the Subleased Premises accruing after the date of such transfer, and it shall be
deemed and construed

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<PAGE>

that any transferee has assumed and shall carry out all covenants and
obligations thereafter to be performed by Sublessor hereunder.

         26. PARKING. Sublessee shall have the right to use throughout the Term
all of the parking spaces, if any, available to Sublessor in the parking lot for
the Premises.

         27. SIGNAGE. Subject to the consent of Master Lessor, if required under
the Master Lease, Sublessee shall have the right to use, install and maintain,
at Sublessee's expense, all signage that Sublessor is permitted to display
pursuant to the terms of the Master Lease.

         28. ADDITIONAL PROVISIONS. The following additional provisions shall
apply: (a) if the Master Lease terminates for any reason, this Sublease shall
terminate concurrently therewith as to the Subleased Premises; (b) Sublessee
shall also have the non-exclusive right to use the common areas outside the
Premises that Sublessor has the right to use under the Master Lease; (c)
Sublessor, with respect to the obligations of Master Lessor under the Master
Lease, shall request Master Lessor in writing to perform such obligations as and
when requested to do so by Sublessee, and to use Sublessor's reasonable efforts
to obtain Master Lessor's performance; (d) Sublessee shall comply with all
restrictions set forth in the Master Lease and all rules and regulations
promulgated from time to time by Master Lessor; (e) except as expressly set
forth in this Sublease, Sublessee shall obtain the prior written consent of
Sublessor and Master Lessor with respect to any act which, if performed by
Sublessor, would require Master Lessor's approval under the Master Lease, and
the consent of Sublessor may be withheld if Master Lessor's consent is not
obtained; and (f) this Sublease shall be at all times subject and subordinate to
the Master Lease.

         29. SUBLESSOR'S REPRESENTATIONS AND WARRANTIES. Sublessor represents
and warrants that (i) the Master Lease is in full force and effect, and there
exists under the Master Lease no default or event of default by either
Sublessor, or to the best of Sublessor's actual knowledge, Master Lessor, nor
has there occurred any event which, with the giving of notice or the passage of
time or both, could constitute such a default or event of default; and (ii) a
true, correct and complete copy of the Master Lease is attached hereto as
EXHIBIT A.

         30. CONSENT OF MASTER LESSOR AND SUBLESSOR. If Sublessee desires to
take any action which requires the consent or approval of Sublessor pursuant to
the terms of this Sublease, prior to taking such action, including, without
limitation, making any alterations, then, notwithstanding anything to the
contrary herein, (a) Sublessor shall have the same rights of approval or
disapproval as Master Lessor has under the Master Lease, and (b) Sublessee shall
not take any such action until it obtains the consent of Sublessor and Master
Lessor, as may be required under this Sublease or the Master Lease. This
Sublease shall not be effective unless and until any required written consent of
the Master Lessor shall have been obtained.

         31. AMENDMENT. This Sublease may not be amended except by the written
agreement of all parties hereto.

         32. BROKERS. Each party hereto hereby represents and warrants that it
has dealt with no broker in connection with this Sublease and the transactions
contemplated herein. Each party shall indemnify, protect, defend and hold
harmless the other from all costs and expenses

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<PAGE>

(including reasonable attorneys' fees) arising from or relating to a breach of
the foregoing representation and warranty.

         33. GUARANTY. Sirenza Microdevices, Inc. shall guaranty the performance
and payment obligations of Sublessee under this Sublease. Upon the mutual
execution of this Sublease, Sirenza Microdevices, Inc. shall execute a guaranty
of sublease in the form of EXHIBIT C attached hereto and made a part hereof (the
"GUARANTY").

         34. MISCELLANEOUS. This Sublease shall in all respects be governed by
and construed in accordance with the laws of the jurisdiction in which the
Subleased Premises are located. If any term of this Sublease is held to be
invalid or unenforceable by any court of competent jurisdiction, then the
remainder of this Sublease shall remain in full force and effect to the fullest
extent possible under the law, and shall not be affected or impaired. Time is of
the essence with respect to the performance of every provision of this Sublease
in which time of performance is a factor. Any executed copy of this Sublease
shall be deemed an original for all purposes. This Sublease shall, subject to
the provisions regarding assignment and subletting, apply to and bind the
respective heirs, successors, executors, administrators and assigns of Sublessor
and Sublessee. The language in all parts of this Sublease shall in all cases be
construed as a whole according to its fair meaning, and not strictly for or
against either Sublessor or Sublessee. The captions used in this Sublease are
for convenience only and shall not be considered in the construction or
interpretation of any provision hereof. When a party is required to do something
by this Sublease, it shall do so at its sole cost and expense without right of
reimbursement from the other party unless specific provision is made therefor.
If either party brings any action or legal proceeding with respect to this
Sublease, the prevailing party shall be entitled to recover reasonable
attorneys' and experts' fees and court costs. This Sublease may be executed in
counterparts.

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<PAGE>

         IN WITNESS WHEREOF, the parties have executed this Sublease as of the
day first above written.

SUBLESSOR:                                    SUBLESSEE:


Vari-L Company, Inc.,                         Olin Acquisition Corporation,
a Colorado corporation                        a Delaware corporation


By: /s/ CHARLES R. BLAND                      By: /s/ THOMAS J. SCANNELL
    ------------------------                      ----------------------

Name: Charles R. Bland                        Name: Thomas J. Scannell
      ----------------------                        --------------------

Its: Chief Executive Officer                  Its:  President
     -----------------------                        --------------------


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<PAGE>

                                    EXHIBIT A

                                  MASTER LEASE

<PAGE>


                                    EXHIBIT B

                               CONSENT TO SUBLEASE

         Master Lessor hereby acknowledges receipt of a copy of that certain
sublease between Vari-L Corporation, as sublessor ("SUBLESSOR") and Olin
Acquisition Corporation as sublessee ("SUBLESSEE"), dated March 31, 2003 (the
"SUBLEASE") concerning those premises located at 4895 Peoria Street, Denver,
Colorado (the "SUBLEASED PREMISES"), and Master Lessor hereby consents to all of
the terms and conditions thereof. All capitalized terms used herein that are not
specifically defined herein shall have the meaning ascribed to them in the
Sublease. Master Lessor further agrees that, notwithstanding anything to the
contrary in the Master Lease:

         1. NOTICE. Master Lessor shall deliver to Sublessee, at the same time
and in the same manner as delivered to Sublessor, a copy of any notice required
to be delivered to Sublessor under the Master Lease.

         2. RIGHT TO CURE. In the event that Sublessor defaults in the
performance or observance of any of Sublessor's obligations under the Master
Lease, Master Lessor agrees that Sublessee shall have the right, but not the
obligation, on behalf of Sublessor to cure any default, of which Sublessee has
notice, within the time available to Sublessor to cure any such default under
the Master Lease, and Master Lessor shall accept such cure from Sublessee. In
addition, Sublessee shall have the right to pay directly to Master Lessor all
rent and other sums owing by Sublessee to Sublessor under the Sublease which are
also owed by Sublessor to Master Lessor under the Master Lease if (i) Sublessee
reasonably believes that Sublessor has failed to make any payment required to be
made by Sublessor to Master Lessor under the Master Lease and Sublessor fails to
provide adequate proof of payment within two (2) business days after Sublessee's
written demand requesting such proof, or (ii) Sublessee reasonably believes that
Sublessor will fail to make any payment required to be made by Sublessor to
Master Lessor under the Master Lease and Sublessor fails to provide assurance of
future performance in form reasonably satisfactory to Sublessee within two (2)
business days after Sublessee's written demand requesting such assurance. Any
sums paid directly by Sublessee to Master Lessor in accordance with this
paragraph shall be credited toward the amounts payable by Sublessee to Sublessor
under the Sublease. In the event Sublessee tenders payment directly to Master
Lessor in accordance with this paragraph and Master Lessor refuses to accept
such payment, Sublessee shall have the right to deposit such funds in an account
with a national bank for the benefit of Master Lessor and Sublessor, and the
deposit of such funds in such an account shall discharge Sublessee's obligation
under this Sublease to make the payment in question.

         3. NON-DISTURBANCE. If the Master Lease terminates prior to expiration
of the term of the Sublease for any reason other than as a result of Master
Lessor's right to terminate the Master Lease for casualty or condemnation as
provided in the Master Lease, then Master Lessor covenants and agrees that this
Sublease shall continue in full force and effect, at Sublessee's option, as a
direct lease between Master Lessor and Sublessee upon all of the terms,
covenants and conditions of the Sublease, and Master Lessor shall recognize
Sublessee's right to possession of the Subleased Premises as provided in the
Sublease and shall not disturb Sublessee's right to possession so long as
Sublessee is not in default under the Sublease beyond the period provided for
the cure of any such default.

                                       2
<PAGE>

         4. ASSIGNMENT AND SUBLETTING. Sublessee may, without Master Lessor's
prior written consent and without payment of any amount to Master Lessor, sublet
the Subleased Premises or assign the Sublease to (i) an entity, controlling,
controlled by, or under common control with Sublessee, (ii) a successor entity
related to Sublessee by merger, consolidation, non-bankruptcy reorganization, or
government action, or (iii) a purchaser of substantially all of Sublessee's
assets located at the Subleased Premises. Neither the sale or transfer of
Sublessee's capital stock shall be deemed an assignment, subletting, or other
transfer of the Sublease or the Subleased Premises.

         5. WAIVER OF SUBROGATION. Notwithstanding anything to the contrary
contained in the Sublease or the Master Lease, Master Lessor and Sublessee each
release the other and their respective agents, employees, successors, assignees
and subtenants from all liability for injury to any person or damage to any
property that is caused by or results from a risk which is actually insured
against, which is required to be insured against under the Master Lease or the
Sublease, or which would normally be covered by "all risk" property insurance,
without regard to the negligence or willful misconduct of the person or entity
so released.

         6. HAZARDOUS MATERIALS. To Master Lessor's best knowledge, (i) no
Hazardous Materials, as defined in the Sublease, are present in the Premises or
at the property where the Premises is situated (the "PROJECT"), (ii) no
underground storage tanks are present at the Premises or at the property where
the Premises is situated, and (iii) no action, proceeding or claim is pending or
threatened regarding the Premises or at the property where the Premises is
situated concerning any Hazardous Materials or pursuant to any environmental
law. Under no circumstance shall Sublessee be liable for, and Master Lessor
shall indemnify, defend and hold harmless Sublessee, its shareholders,
directors, agents, representatives, successors, subtenants and assigns from and
against, all losses, costs, claims, liabilities, and damages (including
reasonable attorneys' fees) directly or indirectly arising in connection with
any Hazardous Materials present at any time on or about the Project or the
violation of any environmental laws, except to the extent that any of the
foregoing actually results from the release of Hazardous Materials by Sublessee
or its agents in violation of environmental laws and regulations.

         7. LIEN; SECURITY INTEREST. Master Lessor shall have no security
interest or lien on any item of Sublessee's trade fixtures, furniture, equipment
and other personal property ("SUBLESSEE'S PROPERTY"). Within ten (10) days after
Sublessee's request, Master Lessor shall execute documents reasonably acceptable
to both parties to evidence Master Lessor's waiver of any right, title, lien, or
interest in Sublessee's Property. Master Lessor waives any right of distraint,
distress for rent or "landlord's lien" that may arise at law.

         8. PARKING. Master Lessor acknowledges that Sublessee is entitled to
all of the parking spaces in the parking lot serving the Subleased Premises.

         9. Intentionally omitted.

         10. Intentionally omitted.

                                       3
<PAGE>

         11. CONSENTS. Whenever the consent or approval of Master Lessor is
required with respect to the Sublease or the Subleased Premises, such consent or
approval shall not be unreasonably withheld or delayed.


                                       4
<PAGE>

         This consent shall be binding upon any successors, assigns or other
transferees of Master Lessor's or Sublessor's interests under the Master Lease
or of Sublessee's pr Sublessor's interests under the Sublease.

         IN WITNESS WHEREOF, the undersigned have executed this Consent to
Sublease as of the 31st day of March, 2003.

MASTER LESSOR:                             SUBLESSOR:


FIVE-K INVESTMENTS,                        VARI-L CORPORATION,
a Colorado general partnership             a Colorado corporation


By: /s/ HAROLD KUNZ                        By: /s/ CHARLES R. BLAND
    ----------------                           ------------------------


Name: Harold Kunz                          Name: Charles R. Bland
      --------------                             ----------------------


Its: General Partner                       Its: Chief Executive Officer
     ---------------                            -----------------------


SUBLESSEE:


OLIN ACQUISITION CORPORATION,
a Delaware corporation


By: /s/ THOMAS J. SCANNELL
    ----------------------


Name: Thomas J. Scannell
      --------------------


Its: President
     ---------------------


                                       5
<PAGE>

                                    EXHIBIT C

                                    GUARANTY

         IN CONSIDERATION OF, and as an inducement to, Vari-L Company, Inc., a
Colorado corporation ("Sublessor"), to enter into that certain Sublease dated of
even date herewith (the "Sublease") with Olin Acquisition Corp., a Delaware
corporation ("Sublessee"), with respect to the Subleased Premises described more
particularly in the Sublease (the "Premises"), the undersigned Guarantor has
executed and delivered this Guaranty as of this 31st day of March, 2003.
Guarantor acknowledges that the current Sublessee under the Sublease is a
wholly-owned subsidiary of Guarantor, that Sublessor would not enter into the
Sublease without this Guaranty, that without this Guaranty Sublessor could elect
not to enter into the Sublease, and that entering into the Sublease is in the
best interests of Sublessee and will benefit Sublessee and therefore that
Guarantor will benefit from Sublessor's entering into the Sublease with
Sublessee.

         1. Guarantor hereby guarantees to Sublessor, its successors and assigns
the full and prompt payment of the Rent (as defined in the Sublease) and all
other sums and charges payable by Sublessee, its successors and assigns, under
the Sublease, and further hereby guarantees the full and timely performance and
observance of all the covenants, terms, conditions and agreements therein
provided to be performed or observed by Sublessee, its successors and assigns.
Guarantor hereby covenants and agrees to and with Sublessor, its successors and
assigns, that if default (beyond applicable notice and cure periods) shall at
any time be made by Sublessee, its successors and assigns, in the payment of any
such Rent and any and all such other sums and charges, or in the performance and
observance of any of the covenants, terms, conditions or agreements contained in
the Sublease, Guarantor shall, within five (5) business days after written
notice to Guarantor, forthwith pay such Rent and other sums and charges, and any
arrears thereof, to Sublessor, its successors and assigns, and shall forthwith
faithfully perform and fulfill all of such terms, covenants, conditions and
agreements, or, with respect to non-monetary defaults only, if the cure of such
defaults cannot reasonably be accomplished within such five (5) business day
period, Guarantor shall (within such period) commence the cure and shall
diligently pursue such cure to completion. Guarantor shall also forthwith pay to
Sublessor all reasonable attorneys' fees and disbursements payable by Sublessee
under the Sublease or incurred by Sublessor in the enforcement of this Guaranty.
Sublessor shall accept Guarantor's payment of such Rent and other sums and
charges due under the Sublease and this Guaranty and Guarantor's performance of
Sublessee's obligations under the Sublease as a cure of Sublessee's failure to
make such payment or perform such obligation in the manner required under the
Sublease.

         2. This Guaranty is an absolute and unconditional guaranty of payment
and of performance. The obligations of Guarantor are independent of the
obligations of Sublessee. This Guaranty shall be enforceable against Guarantor
without the necessity of any suit or proceedings on Sublessor's part of any kind
or nature whatsoever against Sublessee, its successors and assigns, and without
the necessity of any notice of nonpayment, nonperformance or nonobservance,
except as specifically provided above or, with respect to the Sublease, as
provided in the Sublease, or any notice of acceptance of this Guaranty, or any
other notice or demand to which Guarantor might otherwise be entitled, all of
which Guarantor hereby expressly waives. Guarantor hereby expressly agrees that
the validity of this Guaranty and the obligations

                                       6
<PAGE>

of Guarantor hereunder shall in nowise be terminated, affected, diminished or
impaired by reason of the assertion or the failure to assert by Sublessor
against Sublessee, or against Sublessee's successors and assigns, of any of the
rights or remedies reserved to Sublessor pursuant to the provisions of the
Sublease or by relief of Sublessee from any of Sublessee's obligations under the
Sublease or otherwise by (a) the release or discharge of Sublessee in any
creditors' proceedings, receivership, bankruptcy or other proceedings, (b) the
impairment, limitation or modification of the liability of Sublessee or the
estate of Sublessee in bankruptcy, or of any remedy for the enforcement of
Sublessee's liability under the Sublease, resulting from the operation of any
present or future provision of the United States Bankruptcy Code, or (c) the
rejection or disaffirmance of the Sublease in any such proceedings.

         3. This Guaranty shall be a continuing guaranty and the liability of
Guarantor shall in no way be affected, modified or diminished by reason of any
assignment, amendment, renewal, supplement, modification or extension of the
Sublease or by reason of any modification or waiver of or change in any of the
terms, covenants, conditions or provisions of the Sublease, or by reason of any
extension of time that may be granted by Sublessor to Sublessee, its successors
or assigns or a changed or different use of the Premises consented to in writing
by Sublessor, or by reason of any dealings or transactions or matters or things
occurring between Sublessor and Sublessee, its successors or assigns, whether or
not notice thereof is given to Guarantor.

         4. Sublessor's consent to any assignment or assignments, and successive
assignments by Sublessee and Sublessee's assigns of the Sublease, made either
with or without notice to Guarantor, shall in no manner whatsoever release
Guarantor from any liability as Guarantor.

         5. The assignment by Sublessor of the Sublease and/or the avails and
proceeds thereof made either with or without notice to Guarantor shall in no
manner whatsoever release Guarantor from any liability as Guarantor. Sublessor
may without notice to Guarantor assign this Guaranty.

         6. All of Sublessor's rights and remedies under the Sublease or under
this Guaranty are intended to be distinct, separate and cumulative, and no such
right and remedy therein or herein mentioned is intended to be in exclusion of
or a waiver of any of the others. The obligation of Guarantor hereunder shall
not be released by Sublessor's receipt, application or release of security given
for the performance and observance of covenants and conditions required to be
performed and observed by Sublessee under the Sublease, nor shall Guarantor be
released by the maintenance of or execution upon any lien which Sublessor may
have or assert against Sublessee and/or Sublessee's assets.

         7. Until all the covenants and conditions in the Sublease on
Sublessee's part to be performed and observed are fully performed and observed,
Guarantor (a) shall have no right of subrogation against Sublessee by reason of
any payments or acts of performance by Guarantor in compliance with the
obligations of Guarantor hereunder and (b) waives any right to enforce any
remedy which Guarantor now or hereafter shall have against Sublessee by reason
of any one or more payment or acts of performance in compliance with the
obligations of Guarantor hereunder.

                                       7
<PAGE>

         8. Guarantor hereby agrees that this Guaranty shall be governed by the
laws of the State of Colorado.

         9. All notices and demands which Sublessor is required to give or may
elect to give to Guarantor, shall be in writing and shall comply with the
procedures set forth in the Sublease and addressed as set forth below.


                                       8
<PAGE>

         IN WITNESS WHEREOF, the undersigned Guarantor has executed this
Guaranty as of the date set forth below.

                                   GUARANTOR:

                                   SIRENZA MICRODEVICES, INC.,
                                   a Delaware corporation

                                   By: /s/ THOMAS J. SCANNELL
                                       ----------------------

                                   Name: Thomas J. Scannell
                                         --------------------

                                   Its: VP Finance & CFO
                                        ---------------------

                                   Date: 3/26/03
                                         --------------------


Address for notices and service of process:

SIRENZA MICRODEVICES, INC.
522 Almanor Avenue Sunnyvale, CA 94085
Attn: Chief Financial Officer
Telephone: (408) 616-5400
Telecopier: (408) 739-0970

With a copy to:

Wilson Sonsini Goodrich & Rosati, P.C.
650 Page Mill Road Palo Alto, CA 94304
Attention: Steven V. Bernard
Telephone No.: 650-493-9300
Facsimile No.: 650-493-6811


                                       9
<PAGE>

                               CONSENT TO SUBLEASE

            Life Investors Insurance Company of America ("LIICA") hereby
acknowledges receipt of a copy of (a) that certain Sublease (the "Sublease")
between Vari-L Company, Inc. ("Vari-L") and Olin Acquisition Corporation
("Olin") dated March 31, 2003, and (b) that certain Consent to Sublease (the
"Five-K Consent") between Vari-L as sublessor, Olin as sublessee and Five-K
Investments Company ("Five-K") as master lessor, dated April 11, 2003, both
concerning those premises located at 4895 Peoria Street, Denver, Colorado. LIICA
hereby consents to (i) all of the terms and conditions of the Sublease, (ii) all
of the terms and conditions of the Five-K Consent and (iii) the execution by
Five-K of the Five-K Consent, notwithstanding the provisions of that certain
Absolute Assignment of Leases and Rents agreement dated December 15, 1997, and
that certain Subordination, Non-Disturbance and Attornment Agreement dated
December 16, 1997, both between Five-K and LIICA, to the contrary.

            IN WITNESS WHEREOF, the undersigned has executed this Consent to
Sublease as of the 11th day of April, 2003.

LIFE INVESTORS INSURANCE COMPANY OF AMERICA

By:  AEGON USA Realty Advisors, Inc.

Its: /s/ DAVID C. FETTMAN
     --------------------

By: David C. Fettman
    ---------------------

Its: Vice President
     --------------------