X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f
X-Recipient: geda-user AT delorie DOT com
X-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20120113;
        h=mime-version:in-reply-to:references:from:date:message-id:subject:to;
        bh=x1o5CRqBYqNuHQ+dnjzhO5iv09ngoZxHgs5L7HhdjVw=;
        b=OozvFrDFq82krKPYKPxf0QYKkOSFVa04Z2Ezty1DuhYPsERejr6KjdZhI2p4GZ7dKV
         TMc/iF5rAYhDmUMvSrjTLxzuazjVMNn5DaTjx8sjiuR4YhBK6YuH8ClBOVWKML7x0RWx
         kVOD6/+H9h8lusl0AS/bmmyrqJKmLgTyr22sgHVoEnmQUoPh9DBaw0ulbKvJQIJE24zF
         EiTjdr5xNe2vnCQi2lYu9xsiEu1ef4w320Sx7zm6ax6tHKVGtkQIlqVXLFgM0SGnCIlY
         5RxuaHVvdAVlf8bzCEUmSGY8F2NejXNsoK35wkEtS1pyowLxgGErfSmHLmMW5Bddw+ST
         iL0g==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20130820;
        h=x-gm-message-state:mime-version:in-reply-to:references:from:date
         :message-id:subject:to;
        bh=x1o5CRqBYqNuHQ+dnjzhO5iv09ngoZxHgs5L7HhdjVw=;
        b=eSd4H1t73adjpdvtzMDmHMNoPXQgag9bsjcgcGBUSNdupGh8aj57IjYSAz2oDnU57p
         iK/emQZIoz9F/ovQ9Qty23JGzl6M7yASaH4rC9B0auj+2U6tKydSgsZm8oaAHkThoI7Y
         gF+GCs/l1McSJ/9xpUTYXbWwCEeXflS9ygV3xs2yH4CDr035IP/TVaDwvOx19OXSACwr
         RC5iH5i9plHm3dDPgthVfkSzXhpJzO2G+whUmCczNd9BIRLVesRx7hrJKYWfs+WIBxvc
         MeXq8DP2Tp+TIfclsmVSHgBkJ/zWmZU4otBU3MBzTCzVPJxtL1EB+4uIP/Bt9bdkbqwN
         myiA==
X-Gm-Message-State: AE9vXwNYFD6so5ibOeXrKG4p3KvP6KEwNl4i7UnwVcPeefgU7qFbPwgpANxFCiLVIvpVnyYhtLYFyNZiykwO/g==
X-Received: by 10.25.26.193 with SMTP id a184mr5731074lfa.219.1472748154219;
 Thu, 01 Sep 2016 09:42:34 -0700 (PDT)
MIME-Version: 1.0
In-Reply-To: <20160901075118.GA5753@visitor2.iram.es>
References: <0f623d55-c654-88af-ca54-52bb385f51e0 AT neurotica DOT com>
 <20160831041644 DOT GA6695 AT recycle DOT lbl DOT gov> <CAM2RGhRrTihCo7jdrcMdB6JNopHW99XEeM7iP1Esv3xKknzuAg AT mail DOT gmail DOT com>
 <20160831061012 DOT GA6882 AT recycle DOT lbl DOT gov> <CAM2RGhQHNAPUbDhjg24rE4cpMd-Vy_eSHpb1mpM6GY8z8=9tEg AT mail DOT gmail DOT com>
 <20160831171320 DOT GA8813 AT recycle DOT lbl DOT gov> <CAM2RGhT3sbyqy8oHHUM0ELZKt3uC4bmSc2vPHKzQys1GkGRdDw AT mail DOT gmail DOT com>
 <20160831213938 DOT GA9594 AT recycle DOT lbl DOT gov> <CAM2RGhSpi4dLqKQ_X+Uqmkf-ApqBiy0=gMpGLWWnVvoEhorFTA AT mail DOT gmail DOT com>
 <20160901042523 DOT GA10314 AT recycle DOT lbl DOT gov> <20160901075118 DOT GA5753 AT visitor2 DOT iram DOT es>
From: "Evan Foss (evanfoss AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
Date: Thu, 1 Sep 2016 12:42:32 -0400
Message-ID: <CAM2RGhSB8uay4vNf37=wsetL-B3mBq-3TT8bq0mws8W2vPs4oQ@mail.gmail.com>
Subject: Re: [geda-user] Microwave PCB layout simulation or How to eat all
 your processing power in 3 easy steps
To: gEDA users mailing list <geda-user AT delorie DOT com>
Content-Type: text/plain; charset=UTF-8
Reply-To: geda-user AT delorie DOT com
Errors-To: nobody AT delorie DOT com
X-Mailing-List: geda-user AT delorie DOT com
X-Unsubscribes-To: listserv AT delorie DOT com
Precedence: bulk

On Thu, Sep 1, 2016 at 3:51 AM, Gabriel Paubert (paubert AT iram DOT es) [via
geda-user AT delorie DOT com] <geda-user AT delorie DOT com> wrote:
> On Wed, Aug 31, 2016 at 09:25:23PM -0700, Larry Doolittle wrote:
>> Evan -
>>
>> On Thu, Sep 01, 2016 at 12:07:28AM +0000, Evan Foss (evanfoss AT gmail DOT com) [via geda-user AT delorie DOT com] wrote:
>> > On Wed, Aug 31, 2016 at 9:39 PM, Larry Doolittle <ldoolitt AT recycle DOT lbl DOT gov> wrote:
>> > > On Wed, Aug 31, 2016 at 03:53:25PM -0400, Evan Foss (evanfoss AT gmail DOT com) [via geda-user AT delorie DOT com] wrote:
>> > >> I thought soldermask issues were why most of the microwave and other
>> > >> RF hardware I have seen has no soldermask.
>> > > For the long lines, yes, depending on the designer, but eventually
>> > > those lines usually touch chips.  And high-speed serial lanes (with
>> > > the interesting frequency range now going up to 40 GHz) usually don't
>> > > have soldermask stripped off.
>> > At those frequencies I would actually think the chip would be supplied
>> > as bare die and wire bonded.
>>
>> These days Xilinx BGAs have I/O rated for 25 Gb/s, with pretty broad spectral
>> content up to 40 GHz.  I'm used to microwave circuits mostly ranging from
>> 1 - 3 GHz, and all the Mini-Circuits and Hittite chips that cover that range
>> (and higher) are in relatively conventional packages.
>
> Even to higher frequencies, we've been building here amplifiers with
> chips like Hittite's HMC462LP5 and using them up to 12GHz. They are
> specified to up 20GHz, but I can't test that high because we reach the
> limits of the connectors/launchers on the boards we've built.

Cool.

> At these frequencies, the choice of the substrate is important, we use
> 20mil thick Rogers RO4350 (or RO4003, can't remember) but the transition
> from coaxial cable to the controlled impedance track is the most critical
> part: I've had once an enclosure with a mistake of 0.5 or 0.6 mm in the
> depth of the hole in which a glass bead is inserted. The effect on the
> SWR was enormous, catastrophic at 10GHz and higher.

Glass bead?

> For the controlled impedance tracks, we typically use conductor backed
> coplanar waveguide, taking into account the effect of the cover of the
> shielded enclosure on the impedance.

Do you know of a publicly available design guide for those? I was
thinking about how pcb-rnd's new drc system should handle them last
night.

> And no these boards don't have solder masks, for other boards, where I
> also had to wire bond a diode, the solder mask was mostly removed along
> the tracks and the edges of the ground plane. Some was left as solder
> stops to limit solder flow along the track.

I knew it!

>     Gabriel

Thanks,
Evan

-- 
Home
http://evanfoss.googlepages.com/
Work
http://forge.abcd.harvard.edu/gf/project/epl_engineering/wiki/

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v2
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=Ta4p
-----END PGP PUBLIC KEY BLOCK-----